485BPOS

Securities Act of 1933 Registration No. 002-77909

Investment Company Act of 1940 Registration No. 811-03480

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 x

o Pre-Effective Amendment No.  ______

x Post-Effective Amendment No.  _ 92 _

and

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 x

x Amendment No.  _92

Fidelity Oxford Street Trust

 (Exact Name of Registrant as Specified in Charter)

245 Summer Street, Boston, Massachusetts 02210

(Address of Principal Executive Offices)(Zip Code)

Registrant’s Telephone Number: 617-563-7000

William C. Coffey, Secretary

245 Summer Street

Boston, Massachusetts 02210

(Name and Address of Agent for Service)

It is proposed that this filing will become effective immediately upon filing pursuant to paragraph (b) of Rule 485.

EXHIBIT INDEX

Exhibit	Exhibit No.
XBRL Instance Document	EX-101.INS
XBRL Taxonomy Extension Schema Document	EX-101.SCH
XBRL Taxonomy Extension Calculation Linkbase Document	EX-101.CAL
XBRL Taxonomy Extension Definition Linkbase Document	EX-101.DEF
XBRL Taxonomy Extension Labels Linkbase Document	EX-101.LAB
XBRL Taxonomy Extension Presentation Linkbase Document	EX-101.PRE

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for the effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Post-Effective Amendment No. 92to the Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Boston, and Commonwealth of Massachusetts, on the 16th day of October 2018.

	Fidelity Oxford Street Trust
	By	/s/Laura M. Del Prato
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||		Laura M. Del Prato, President

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.

(Signature)		(Title)	(Date)
/s/Laura M. Del Prato		President and Treasurer	October 16, 2018
Laura M. Del Prato		(Principal Executive Officer)
/s/John J. Burke III		Chief Financial Officer	October 16, 2018
John J. Burke III		(Principal Financial Officer)
/s/Abigail P. Johnson	†	Trustee	October 16, 2018
Abigail P. Johnson
/s/Elizabeth S. Acton	*	Trustee	October 16, 2018
Elizabeth S. Acton
/s/John Engler	*	Trustee	October 16, 2018
John Engler
/s/Albert R. Gamper, Jr.	*	Trustee	October 16, 2018
Albert R. Gamper, Jr.
/s/Robert F. Gartland	*	Trustee	October 16, 2018
Robert F. Gartland
/s/Arthur E. Johnson	*	Trustee	October 16, 2018
Arthur E. Johnson
/s/Michael E. Kenneally	*	Trustee	October 16, 2018
Michael E. Kenneally
/s/Marie L. Knowles	*	Trustee	October 16, 2018
Marie L. Knowles
/s/Mark A. Murray	*	Trustee	October 16, 2018
Mark A. Murray
/s/Jennifer Toolin McAuliffe	*	Trustee	October 16, 2018
Jennifer Toolin McAuliffe

†	By:	/s/ Kevin M. Meagher
		Kevin M. Meagher, pursuant to a power of attorney dated September 30, 2018 and filed herewith.
*	By:	/s/Megan C. Johnson
		Megan C. Johnson, pursuant to a power of attorney dated September 1, 2017 and filed herewith.

POWER OF ATTORNEY

I, the undersigned Trustee of the following investment companies:

Fidelity Aberdeen Street Trust Fidelity Advisor Series II Fidelity Advisor Series IV Fidelity Boylston Street Trust Fidelity California Municipal Trust Fidelity California Municipal Trust II Fidelity Central Investment Portfolios II LLC Fidelity Charles Street Trust Fidelity Colchester Street Trust Fidelity Court Street Trust Fidelity Court Street Trust II Fidelity Garrison Street Trust Fidelity Hereford Street Trust Fidelity Income Fund Fidelity Massachusetts Municipal Trust
Fidelity Merrimack Street Trust Fidelity Money Market Trust Fidelity Municipal Trust Fidelity Municipal Trust II Fidelity Newbury Street Trust Fidelity New York Municipal Trust Fidelity New York Municipal Trust II Fidelity Oxford Street Trust Fidelity Oxford Street Trust II Fidelity Phillips Street Trust Fidelity Revere Street Trust Fidelity Salem Street Trust Fidelity School Street Trust Fidelity Union Street Trust Fidelity Union Street Trust II Variable Insurance Products Fund V

in addition to any other Fidelity Fund for which the undersigned individual serves as Trustee (collectively, the “Funds”), hereby constitute and appoint Kevin M. Meagher, my true and lawful attorney-in-fact, with full power of substitution, and with full power to sign for me and in my name in the appropriate capacity, all Registration Statements of the Funds on Form N-1A, or any successors thereto, any and all subsequent Amendments, Pre-Effective Amendments, or Post-Effective Amendments to said Registration Statements or any successors thereto, and any supplements or other instruments in connection therewith, and generally to do all such things in my name and behalf in connection therewith as said attorney-in-fact deems necessary or appropriate, to comply with the provisions of the Securities Act of 1933 and the Investment Company Act of 1940, and all related requirements of the Securities and Exchange Commission.  I hereby ratify and confirm all that said attorney-in-fact or his substitutes may do or cause to be done by virtue hereof.  

This Power of Attorney shall remain in full force and effect only for such time as Kevin M. Meagher shall continue to be an officer of Fidelity Management & Research Company, provided that, notwithstanding the foregoing, this Power of Attorney may be revoked at any time by the undersigned in writing.

This Power of Attorney has been executed as of September 30, 2018.

/s/Abigail P. Johnson

Abigail P. Johnson

POWER OF ATTORNEY

We, the undersigned Directors or Trustees, as the case may be, of the following investment companies:

Fidelity Aberdeen Street Trust Fidelity Advisor Series II Fidelity Advisor Series IV Fidelity Boylston Street Trust Fidelity California Municipal Trust Fidelity California Municipal Trust II Fidelity Central Investment Portfolios II LLC Fidelity Charles Street Trust Fidelity Colchester Street Trust Fidelity Court Street Trust Fidelity Court Street Trust II Fidelity Garrison Street Trust Fidelity Hereford Street Trust Fidelity Income Fund Fidelity Massachusetts Municipal Trust Fidelity Merrimack Street Trust Fidelity Money Market Trust Fidelity Municipal Trust Fidelity Municipal Trust II Fidelity Newbury Street Trust Fidelity New York Municipal Trust Fidelity New York Municipal Trust II Fidelity Oxford Street Trust Fidelity Oxford Street Trust II Fidelity Phillips Street Trust Fidelity Revere Street Trust Fidelity Salem Street Trust Fidelity School Street Trust Fidelity Union Street Trust Fidelity Union Street Trust II Variable Insurance Products Fund V

in addition to any other Fidelity Fund for which the undersigned individuals serve as Directors or Trustees (collectively, the “Funds”), hereby revoke all previous powers of attorney we have given to sign and otherwise act in our names and behalf in matters involving any investment company for which FMR or an affiliate acts as investment adviser and hereby constitute and appoint Thomas C. Bogle, John V. O’Hanlon, Robert W. Helm, Megan C. Johnson, and Anthony H. Zacharski, each of them singly, our true and lawful attorneys-in-fact, with full power of substitution, and with full power to each of them, to sign for us and in our names in the appropriate capacities, all Registration Statements of the Funds on Form N-1A, or any successors thereto, any and all subsequent Amendments, Pre-Effective Amendments, or Post-Effective Amendments to said Registration Statements or any successors thereto, and any supplements or other instruments in connection therewith, and generally to do all such things in our names and behalf in connection therewith as said attorneys-in-fact deem necessary or appropriate, to comply with the provisions of the Securities Act of 1933 and the Investment Company Act of 1940, and all related requirements of the Securities and Exchange Commission.  We hereby ratify and confirm all that said attorneys-in-fact or their substitutes may do or cause to be done by virtue hereof.  This power of attorney is effective for all documents filed on or after September 1, 2017.

WITNESS our hands on this first day of September 2017.

/s/Elizabeth S. Acton	/s/Michael E. Kenneally
Elizabeth S. Acton	Michael E. Kenneally
/s/John Engler	/s/Marie L. Knowles
John Engler	Marie L. Knowles
/s/Albert R. Gamper, Jr.	/s/Jennifer Toolin McAuliffe
Albert R. Gamper, Jr.	Jennifer Toolin McAuliffe
/s/Robert F. Gartland	/s/Mark A. Murray
Robert F. Gartland	Mark A. Murray
/s/Arthur E. Johnson
Arthur E. Johnson

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Jul. 31, 2018
Registrant Name	dei_EntityRegistrantName	FIDELITY OXFORD STREET TRUST
Central Index Key	dei_EntityCentralIndexKey	0000028540
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Sep. 27, 2018
Document Effective Date	dei_DocumentEffectiveDate	Sep. 29, 2018
Prospectus Date	rr_ProspectusDate	Sep. 29, 2018

XML

07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 | Fidelity® Series Commodity Strategy Fund

<p style="font: bold 20pt Arial, Helvetica, sans-serif;">Fund Summary</p><p style="font: bold 12pt Arial, Helvetica, sans-serif;">Fund:<br/>Fidelity® Series Commodity Strategy Fund</p>

<font style="font: bold 16pt Arial, Helvetica, sans-serif;">Investment Objective</font>

The fund seeks to provide investment returns that correspond to the performance of the commodities market.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Fee Table</b></font>

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Shareholder fees</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px"></p>

Shareholder Fees {- Fidelity® Series Commodity Strategy Fund}	07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 Fidelity® Series Commodity Strategy Fund USD ($)
(fees paid directly from your investment)	none

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Annual Operating Expenses</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">(expenses that you pay each year as a % of the value of your investment)</p>

Annual Operating Expenses {- Fidelity® Series Commodity Strategy Fund}	07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 Fidelity® Series Commodity Strategy Fund Fidelity Series Commodity Strategy Fund-Default
Management fee	none
Distribution and/or Service (12b-1) fees	none
Other expenses	none
Acquired fund fees and expenses	0.05%	[1]
Total annual operating expenses	0.05%

This example helps compare the cost of investing in the fund with the cost of investing in other funds.

Let's say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

<p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Sell All Shares</p>

Expense Example {- Fidelity® Series Commodity Strategy Fund}	07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 Fidelity® Series Commodity Strategy Fund Fidelity Series Commodity Strategy Fund-Default USD ($)
1 year	$ 5
3 years	16
5 years	28
10 years	$ 64

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Portfolio Turnover</b></font>

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 0% of the average value of its portfolio.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Strategies</b></font>

• Normally investing in commodity-linked derivative instruments, short-term investment-grade debt securities, cash, and cash equivalents.

• Investing up to 25% of assets in a wholly-owned subsidiary organized under the laws of the Cayman Islands that invests in commodity-linked total return swaps based on the value of commodities or commodities indexes and in other commodity-linked derivative instruments.

• Managing the fund to track an index chosen to represent the commodities market, as well as short-term investment-grade debt securities, which as of July 31, 2018 was the Bloomberg Commodity Index Total Return℠.

• Investing in domestic and foreign issuers.

• Engaging in commodity-linked derivatives transactions that have a leveraging effect on the fund.

• Investing in Fidelity's central funds (specialized investment vehicles used by Fidelity^® funds to invest in particular security types or investment disciplines).

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Risks</b></font>

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market.

• Financial Services Exposure. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations.

• Subsidiary Risk. Investment in an unregistered subsidiary is not subject to the investor protections of the Investment Company Act of 1940 (1940 Act) and is subject to the risks associated with investing in derivatives and commodity-linked investing in general. Changes in tax and other laws could negatively affect investments in the subsidiary.

• Prepayment. The ability of an issuer of a debt security to repay principal prior to a security's maturity can cause greater price volatility if interest rates change.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. A decline in the credit quality of an issuer or a provider of credit support or a maturity-shortening structure for a security can cause the price of a security to decrease.

• Leverage Risk. Leverage can increase market exposure, magnify investment risks, and cause losses to be realized more quickly.

• Commodity-Linked Investing. The value of commodities and commodity-linked investments may be affected by the performance of the overall commodities markets as well as weather, political, tax, and other regulatory and market developments. Commodity-linked investments may be more volatile and less liquid than the underlying commodity, instruments, or measures.

• Commodity Futures. Investments in commodity futures contracts are also subject to the risk of the failure of any of the exchanges on which the fund’s positions trade or of its clearinghouses or counterparties. In addition, certain commodity exchanges limit fluctuations in certain futures contract prices during a single day by regulations referred to as "daily price fluctuation limits" or "daily limits." Under such daily limits, during a single trading day no trades may be executed at prices beyond the daily limit. If triggered, these limits could prevent the fund from liquidating unfavorable positions and subject the fund to losses or prevent it from entering into desired trades during the particular trading day.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Performance</b></font>

The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for more recent performance information.

<p style="font:bold 11pt Arial, sans-serif; margin-bottom: 0px;">Year-by-Year Returns</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Calendar Years</p>

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	15.54%	December 31, 2010
Lowest Quarter Return	-14.53%	September 30, 2015
Year-to-Date Return	0.00%	June 30, 2018

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Average Annual Returns</b></font>

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.

For the periods ended December 31, 2017

Average Annual Total Returns{- Fidelity® Series Commodity Strategy Fund} - 07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 - Fidelity® Series Commodity Strategy Fund	Past 1 year	Past 5 years	Since Inception	[1]	Inception Date
Fidelity Series Commodity Strategy Fund-Default					Oct. 01, 2009
Fidelity Series Commodity Strategy Fund-Default | Return Before Taxes	0.92%	(9.07%)	(4.66%)
Fidelity Series Commodity Strategy Fund-Default | After Taxes on Distributions	0.68%	(9.12%)	(5.44%)		Oct. 01, 2009
Fidelity Series Commodity Strategy Fund-Default | After Taxes on Distributions and Sales	0.52%	(6.60%)	(3.33%)		Oct. 01, 2009
Bloomberg® Commodity Index Total Return(reflects no deduction for fees, expenses, or taxes)	1.70%	(8.45%)	(3.98%)

[1] The fund may invest in a wholly-owned subsidiary. The subsidiary has entered into a separate contract with Geode Capital Management, LLC (Geode) for the management of its portfolio pursuant to which the subsidiary pays Geode a fee at an annual rate of 0.30% of its net assets. The subsidiary also pays certain other expenses including custody fees.

[1] From October 1, 2009

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY OXFORD STREET TRUST

Prospectus Date

rr_ProspectusDate

Sep. 29, 2018

07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 | Fidelity® Series Commodity Strategy Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

<p style="font: bold 20pt Arial, Helvetica, sans-serif;">Fund Summary</p><p style="font: bold 12pt Arial, Helvetica, sans-serif;">Fund:<br/>Fidelity® Series Commodity Strategy Fund</p>

Objective [Heading]

rr_ObjectiveHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;">Investment Objective</font>

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks to provide investment returns that correspond to the performance of the commodities market.

Expense [Heading]

rr_ExpenseHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Fee Table</b></font>

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Shareholder fees</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px"></p>

(fees paid directly from your investment)

rr_ShareholderFeeOther

none

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Annual Operating Expenses</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">(expenses that you pay each year as a % of the value of your investment)</p>

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Portfolio Turnover</b></font>

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 0% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

none

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example helps compare the cost of investing in the fund with the cost of investing in other funds.

Let's say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

<p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Sell All Shares</p>

Strategy [Heading]

rr_StrategyHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Strategies</b></font>

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing in commodity-linked derivative instruments, short-term investment-grade debt securities, cash, and cash equivalents.

• Investing up to 25% of assets in a wholly-owned subsidiary organized under the laws of the Cayman Islands that invests in commodity-linked total return swaps based on the value of commodities or commodities indexes and in other commodity-linked derivative instruments.

• Managing the fund to track an index chosen to represent the commodities market, as well as short-term investment-grade debt securities, which as of July 31, 2018 was the Bloomberg Commodity Index Total Return℠.

• Investing in domestic and foreign issuers.

• Engaging in commodity-linked derivatives transactions that have a leveraging effect on the fund.

• Investing in Fidelity's central funds (specialized investment vehicles used by Fidelity^® funds to invest in particular security types or investment disciplines).

Risk [Heading]

rr_RiskHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Risks</b></font>

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market.

• Financial Services Exposure. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations.

• Subsidiary Risk. Investment in an unregistered subsidiary is not subject to the investor protections of the Investment Company Act of 1940 (1940 Act) and is subject to the risks associated with investing in derivatives and commodity-linked investing in general. Changes in tax and other laws could negatively affect investments in the subsidiary.

• Prepayment. The ability of an issuer of a debt security to repay principal prior to a security's maturity can cause greater price volatility if interest rates change.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. A decline in the credit quality of an issuer or a provider of credit support or a maturity-shortening structure for a security can cause the price of a security to decrease.

• Leverage Risk. Leverage can increase market exposure, magnify investment risks, and cause losses to be realized more quickly.

• Commodity-Linked Investing. The value of commodities and commodity-linked investments may be affected by the performance of the overall commodities markets as well as weather, political, tax, and other regulatory and market developments. Commodity-linked investments may be more volatile and less liquid than the underlying commodity, instruments, or measures.

• Commodity Futures. Investments in commodity futures contracts are also subject to the risk of the failure of any of the exchanges on which the fund’s positions trade or of its clearinghouses or counterparties. In addition, certain commodity exchanges limit fluctuations in certain futures contract prices during a single day by regulations referred to as "daily price fluctuation limits" or "daily limits." Under such daily limits, during a single trading day no trades may be executed at prices beyond the daily limit. If triggered, these limits could prevent the fund from liquidating unfavorable positions and subject the fund to losses or prevent it from entering into desired trades during the particular trading day.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

Risk Lose Money [Text]

rr_RiskLoseMoney

<font style="FONT-FAMILY: Times New Roman" size="3">You could lose money by investing in the fund.</font>

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

<font style="FONT-FAMILY: Times New Roman" size="3">An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.</font>

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Performance</b></font>

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for more recent performance information.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

<font style="FONT-FAMILY: Times New Roman" size="3">The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.</font>

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<font style="FONT-FAMILY: Times New Roman" size="3">www.fidelity.com</font>

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

<font style="FONT-FAMILY: Times New Roman" size="3">Past performance (before and after taxes) is not an indication of future performance.</font>

Bar Chart [Heading]

rr_BarChartHeading

<p style="font:bold 11pt Arial, sans-serif; margin-bottom: 0px;">Year-by-Year Returns</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Calendar Years</p>

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	15.54%	December 31, 2010
Lowest Quarter Return	-14.53%	September 30, 2015
Year-to-Date Return	0.00%	June 30, 2018

Performance Table Heading

rr_PerformanceTableHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Average Annual Returns</b></font>

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

<font style="FONT-FAMILY: Times New Roman" size="3">After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.</font>

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

<font style="FONT-FAMILY: Times New Roman" size="3">The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).</font>

Performance Table Explanation after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

<font style="FONT-FAMILY: Times New Roman" size="3">Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.</font>

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.

For the periods ended December 31, 2017

07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 | Fidelity® Series Commodity Strategy Fund | Fidelity Series Commodity Strategy Fund-Default

Risk/Return:

rr_RiskReturnAbstract

Management fee

rr_ManagementFeesOverAssets

none

Distribution and/or Service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

none

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.05%

^[1]

Total annual operating expenses

rr_ExpensesOverAssets

0.05%

1 year

rr_ExpenseExampleYear01

$ 5

3 years

rr_ExpenseExampleYear03

16

5 years

rr_ExpenseExampleYear05

28

10 years

rr_ExpenseExampleYear10

$ 64

2010

rr_AnnualReturn2010

15.96%

2011

rr_AnnualReturn2011

(13.89%)

2012

rr_AnnualReturn2012

(1.79%)

2013

rr_AnnualReturn2013

(10.00%)

2014

rr_AnnualReturn2014

(17.55%)

2015

rr_AnnualReturn2015

(25.27%)

2016

rr_AnnualReturn2016

11.07%

2017

rr_AnnualReturn2017

0.92%

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-Date Return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2018

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

none

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

15.54%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2015

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(14.53%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 01, 2009

07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 | Fidelity® Series Commodity Strategy Fund | Return Before Taxes | Fidelity Series Commodity Strategy Fund-Default

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity® Series Commodity Strategy Fund

Label

rr_AverageAnnualReturnLabel

<font style="FONT-FAMILY: Times New Roman" ><b>Return Before Taxes</b></font>

Past 1 year

rr_AverageAnnualReturnYear01

0.92%

Past 5 years

rr_AverageAnnualReturnYear05

(9.07%)

Since Inception

rr_AverageAnnualReturnSinceInception

(4.66%)

^[2]

07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 | Fidelity® Series Commodity Strategy Fund | After Taxes on Distributions | Fidelity Series Commodity Strategy Fund-Default

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity® Series Commodity Strategy Fund

Label

rr_AverageAnnualReturnLabel

<font style="FONT-FAMILY: Times New Roman" ><b>Return After Taxes on Distributions</b></font>

Past 1 year

rr_AverageAnnualReturnYear01

0.68%

Past 5 years

rr_AverageAnnualReturnYear05

(9.12%)

Since Inception

rr_AverageAnnualReturnSinceInception

(5.44%)

^[2]

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 01, 2009

07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 | Fidelity® Series Commodity Strategy Fund | After Taxes on Distributions and Sales | Fidelity Series Commodity Strategy Fund-Default

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity® Series Commodity Strategy Fund

Label

rr_AverageAnnualReturnLabel

<font style="FONT-FAMILY: Times New Roman" ><b>Return After Taxes on Distributions and Sale of Fund Shares</b></font>

Past 1 year

rr_AverageAnnualReturnYear01

0.52%

Past 5 years

rr_AverageAnnualReturnYear05

(6.60%)

Since Inception

rr_AverageAnnualReturnSinceInception

(3.33%)

^[2]

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 01, 2009

07.31 Fidelity Series Commodity Strategy Fund Series PRO-05 | Fidelity® Series Commodity Strategy Fund | Bloomberg® Commodity Index Total Return(reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Past 1 year

rr_AverageAnnualReturnYear01

1.70%

Past 5 years

rr_AverageAnnualReturnYear05

(8.45%)

Since Inception

rr_AverageAnnualReturnSinceInception

(3.98%)

^[2]

[1] The fund may invest in a wholly-owned subsidiary. The subsidiary has entered into a separate contract with Geode Capital Management, LLC (Geode) for the management of its portfolio pursuant to which the subsidiary pays Geode a fee at an annual rate of 0.30% of its net assets. The subsidiary also pays certain other expenses including custody fees.

[2] From October 1, 2009

XML

07.31 Fidelity Commodity Strategy Fund Retail PRO-03 | Fidelity® Commodity Strategy Fund

<p style="font: bold 20pt Arial, Helvetica, sans-serif;">Fund Summary</p><p style="font: normal 12pt Arial, Helvetica, sans-serif;"><b>Fund/Class</b>:<br/><b>Fidelity® Commodity Strategy Fund</b>/Fidelity® Commodity Strategy Fund</p>

<font style="font: bold 16pt Arial, Helvetica, sans-serif;">Investment Objective</font>

The fund seeks to provide investment returns that correspond to the performance of the commodities market.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Fee Table</b></font>

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Shareholder fees</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px"></p>

Shareholder Fees {- Fidelity® Commodity Strategy Fund}	07.31 Fidelity Commodity Strategy Fund Retail PRO-03 Fidelity® Commodity Strategy Fund USD ($)
(fees paid directly from your investment)	none

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Annual Operating Expenses</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">(expenses that you pay each year as a % of the value of your investment)</p>

Annual Operating Expenses {- Fidelity® Commodity Strategy Fund}	07.31 Fidelity Commodity Strategy Fund Retail PRO-03 Fidelity® Commodity Strategy Fund Fidelity Commodity Strategy Fund-Series Class
Management fee	0.40%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.20%
Acquired fund fees and expenses	0.05%	[1]
Total annual operating expenses	0.65%
Fee waiver and/or expense reimbursement	0.05%	[1]
Total annual operating expenses after fee waiver and/or expense reimbursement	0.60%

This example helps compare the cost of investing in the fund with the cost of investing in other funds.

Let's say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

<p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Sell All Shares</p>

Expense Example {- Fidelity® Commodity Strategy Fund}	07.31 Fidelity Commodity Strategy Fund Retail PRO-03 Fidelity® Commodity Strategy Fund Fidelity Commodity Strategy Fund-Series Class USD ($)
1 year	$ 61
3 years	192
5 years	335
10 years	$ 750

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Portfolio Turnover</b></font>

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 0% of the average value of its portfolio.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Strategies</b></font>

• Normally investing in commodity-linked derivative instruments, short-term investment-grade debt securities, cash, and cash equivalents.

• Investing up to 25% of assets in a wholly-owned subsidiary organized under the laws of the Cayman Islands that invests in commodity-linked total return swaps based on the value of commodities or commodities indexes and in other commodity-linked derivative instruments.

• Managing the fund to track an index chosen to represent the commodities market, as well as short-term investment-grade debt securities, which as of July 31, 2018 was the Bloomberg Commodity Index Total Return℠.

• Investing in domestic and foreign issuers.

• Engaging in commodity-linked derivatives transactions that have a leveraging effect on the fund.

• Investing in Fidelity's central funds (specialized investment vehicles used by Fidelity^® funds to invest in particular security types or investment disciplines).

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Risks</b></font>

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market.

• Financial Services Exposure. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations.

• Subsidiary Risk. Investment in an unregistered subsidiary is not subject to the investor protections of the Investment Company Act of 1940 (1940 Act) and is subject to the risks associated with investing in derivatives and commodity-linked investing in general. Changes in tax and other laws could negatively affect investments in the subsidiary.

• Prepayment. The ability of an issuer of a debt security to repay principal prior to a security's maturity can cause greater price volatility if interest rates change.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. A decline in the credit quality of an issuer or a provider of credit support or a maturity-shortening structure for a security can cause the price of a security to decrease.

• Leverage Risk. Leverage can increase market exposure, magnify investment risks, and cause losses to be realized more quickly.

• Commodity-Linked Investing. The value of commodities and commodity-linked investments may be affected by the performance of the overall commodities markets as well as weather, political, tax, and other regulatory and market developments. Commodity-linked investments may be more volatile and less liquid than the underlying commodity, instruments, or measures.

• Commodity Futures. Investments in commodity futures contracts are also subject to the risk of the failure of any of the exchanges on which the fund’s positions trade or of its clearinghouses or counterparties. In addition, certain commodity exchanges limit fluctuations in certain futures contract prices during a single day by regulations referred to as "daily price fluctuation limits" or "daily limits." Under such daily limits, during a single trading day no trades may be executed at prices beyond the daily limit. If triggered, these limits could prevent the fund from liquidating unfavorable positions and subject the fund to losses or prevent it from entering into desired trades during the particular trading day.

In addition, the fund is classified as non-diversified under the Investment Company Act of 1940, which means that it has the ability to invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Performance</b></font>

Performance history will be available for the fund after the fund has been in operation for one calendar year.

[1] The fund may invest in a wholly-owned subsidiary. The subsidiary has entered into a separate contract with Geode Capital Management, LLC (Geode) for the management of its portfolio pursuant to which the subsidiary pays Geode a fee at an annual rate of 0.30% of its net assets. The subsidiary also pays certain other expenses including custody fees. Geode has contractually agreed to waive the fund's management fee in an amount equal to the management fee paid to Geode by the subsidiary. This arrangement will remain in effect for at least one year from the effective date of the prospectus, and will remain in effect thereafter as long as Geode's contract with the subsidiary is in place. If Geode's contract with the subsidiary is terminated, Geode, in its sole discretion, may discontinue the arrangement.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY OXFORD STREET TRUST

Prospectus Date

rr_ProspectusDate

Sep. 29, 2018

07.31 Fidelity Commodity Strategy Fund Retail PRO-03 | Fidelity® Commodity Strategy Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

<p style="font: bold 20pt Arial, Helvetica, sans-serif;">Fund Summary</p><p style="font: normal 12pt Arial, Helvetica, sans-serif;"><b>Fund/Class</b>:<br/><b>Fidelity® Commodity Strategy Fund</b>/Fidelity® Commodity Strategy Fund</p>

Objective [Heading]

rr_ObjectiveHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;">Investment Objective</font>

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks to provide investment returns that correspond to the performance of the commodities market.

Expense [Heading]

rr_ExpenseHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Fee Table</b></font>

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Shareholder fees</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px"></p>

(fees paid directly from your investment)

rr_ShareholderFeeOther

none

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Annual Operating Expenses</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">(expenses that you pay each year as a % of the value of your investment)</p>

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Portfolio Turnover</b></font>

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 0% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

none

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example helps compare the cost of investing in the fund with the cost of investing in other funds.

Let's say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

<p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Sell All Shares</p>

Strategy [Heading]

rr_StrategyHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Strategies</b></font>

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing in commodity-linked derivative instruments, short-term investment-grade debt securities, cash, and cash equivalents.

• Investing up to 25% of assets in a wholly-owned subsidiary organized under the laws of the Cayman Islands that invests in commodity-linked total return swaps based on the value of commodities or commodities indexes and in other commodity-linked derivative instruments.

• Managing the fund to track an index chosen to represent the commodities market, as well as short-term investment-grade debt securities, which as of July 31, 2018 was the Bloomberg Commodity Index Total Return℠.

• Investing in domestic and foreign issuers.

• Engaging in commodity-linked derivatives transactions that have a leveraging effect on the fund.

• Investing in Fidelity's central funds (specialized investment vehicles used by Fidelity^® funds to invest in particular security types or investment disciplines).

Risk [Heading]

rr_RiskHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Risks</b></font>

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market.

• Financial Services Exposure. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations.

• Subsidiary Risk. Investment in an unregistered subsidiary is not subject to the investor protections of the Investment Company Act of 1940 (1940 Act) and is subject to the risks associated with investing in derivatives and commodity-linked investing in general. Changes in tax and other laws could negatively affect investments in the subsidiary.

• Prepayment. The ability of an issuer of a debt security to repay principal prior to a security's maturity can cause greater price volatility if interest rates change.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. A decline in the credit quality of an issuer or a provider of credit support or a maturity-shortening structure for a security can cause the price of a security to decrease.

• Leverage Risk. Leverage can increase market exposure, magnify investment risks, and cause losses to be realized more quickly.

• Commodity-Linked Investing. The value of commodities and commodity-linked investments may be affected by the performance of the overall commodities markets as well as weather, political, tax, and other regulatory and market developments. Commodity-linked investments may be more volatile and less liquid than the underlying commodity, instruments, or measures.

• Commodity Futures. Investments in commodity futures contracts are also subject to the risk of the failure of any of the exchanges on which the fund’s positions trade or of its clearinghouses or counterparties. In addition, certain commodity exchanges limit fluctuations in certain futures contract prices during a single day by regulations referred to as "daily price fluctuation limits" or "daily limits." Under such daily limits, during a single trading day no trades may be executed at prices beyond the daily limit. If triggered, these limits could prevent the fund from liquidating unfavorable positions and subject the fund to losses or prevent it from entering into desired trades during the particular trading day.

In addition, the fund is classified as non-diversified under the Investment Company Act of 1940, which means that it has the ability to invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

Risk Lose Money [Text]

rr_RiskLoseMoney

<font style="FONT-FAMILY: Times New Roman" size="3">You could lose money by investing in the fund.</font>

Risk Nondiversified Status [Text]

rr_RiskNondiversifiedStatus

<font style="FONT-FAMILY: Times New Roman" size="3">In addition, the fund is classified as non-diversified under the Investment Company Act of 1940, which means that it has the ability to invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.</font>

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

<font style="FONT-FAMILY: Times New Roman" size="3">An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.</font>

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Performance</b></font>

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

Performance history will be available for the fund after the fund has been in operation for one calendar year.

Performance One Year or Less [Text]

rr_PerformanceOneYearOrLess

<font style="FONT-FAMILY: Times New Roman" size="3">Performance history will be available for the fund after the fund has been in operation for one calendar year.</font>

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<font style="FONT-FAMILY: Times New Roman" size="3">www.fidelity.com</font>

07.31 Fidelity Commodity Strategy Fund Retail PRO-03 | Fidelity® Commodity Strategy Fund | Fidelity Commodity Strategy Fund-Series Class

Risk/Return:

rr_RiskReturnAbstract

Management fee

rr_ManagementFeesOverAssets

0.40%

Distribution and/or Service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.20%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.05%

^[1]

Total annual operating expenses

rr_ExpensesOverAssets

0.65%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.05%

^[1]

Total annual operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

0.60%

1 year

rr_ExpenseExampleYear01

$ 61

3 years

rr_ExpenseExampleYear03

192

5 years

rr_ExpenseExampleYear05

335

10 years

rr_ExpenseExampleYear10

$ 750

[1] The fund may invest in a wholly-owned subsidiary. The subsidiary has entered into a separate contract with Geode Capital Management, LLC (Geode) for the management of its portfolio pursuant to which the subsidiary pays Geode a fee at an annual rate of 0.30% of its net assets. The subsidiary also pays certain other expenses including custody fees. Geode has contractually agreed to waive the fund's management fee in an amount equal to the management fee paid to Geode by the subsidiary. This arrangement will remain in effect for at least one year from the effective date of the prospectus, and will remain in effect thereafter as long as Geode's contract with the subsidiary is in place. If Geode's contract with the subsidiary is terminated, Geode, in its sole discretion, may discontinue the arrangement.

XML

07.31 Fidelity Commodity Strategy Fund F PRO-03 | Fidelity® Commodity Strategy Fund

<p style="font: bold 20pt Arial, Helvetica, sans-serif;">Fund Summary</p><p style="font: normal 12pt Arial, Helvetica, sans-serif;"><b>Fund/Class</b>:<br/><b>Fidelity® Commodity Strategy Fund</b>/F</p>

<font style="font: bold 16pt Arial, Helvetica, sans-serif;">Investment Objective</font>

The fund seeks to provide investment returns that correspond to the performance of the commodities market.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Fee Table</b></font>

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Shareholder fees</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px"></p>

Shareholder Fees {- Fidelity® Commodity Strategy Fund}	07.31 Fidelity Commodity Strategy Fund F PRO-03 Fidelity® Commodity Strategy Fund USD ($)
(fees paid directly from your investment)	none

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Annual Operating Expenses</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">(expenses that you pay each year as a % of the value of your investment)</p>

Annual Operating Expenses {- Fidelity® Commodity Strategy Fund}	07.31 Fidelity Commodity Strategy Fund F PRO-03 Fidelity® Commodity Strategy Fund Fidelity Commodity Strategy Fund-Class F Fidelity
Management fee	0.40%
Distribution and/or Service (12b-1) fees	none
Other expenses	none
Acquired fund fees and expenses	0.05%	[1]
Total annual operating expenses	0.45%
Fee waiver and/or expense reimbursement	0.05%	[1]
Total annual operating expenses after fee waiver and/or expense reimbursement	0.40%

This example helps compare the cost of investing in the fund with the cost of investing in other funds.

Let's say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

<p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Sell All Shares</p>

Expense Example {- Fidelity® Commodity Strategy Fund}	07.31 Fidelity Commodity Strategy Fund F PRO-03 Fidelity® Commodity Strategy Fund Fidelity Commodity Strategy Fund-Class F Fidelity USD ($)
1 year	$ 41
3 years	128
5 years	224
10 years	$ 505

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Portfolio Turnover</b></font>

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 0% of the average value of its portfolio.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Strategies</b></font>

• Normally investing in commodity-linked derivative instruments, short-term investment-grade debt securities, cash, and cash equivalents.

• Investing up to 25% of assets in a wholly-owned subsidiary organized under the laws of the Cayman Islands that invests in commodity-linked total return swaps based on the value of commodities or commodities indexes and in other commodity-linked derivative instruments.

• Managing the fund to track an index chosen to represent the commodities market, as well as short-term investment-grade debt securities, which as of July 31, 2018 was the Bloomberg Commodity Index Total Return℠.

• Investing in domestic and foreign issuers.

• Engaging in commodity-linked derivatives transactions that have a leveraging effect on the fund.

• Investing in Fidelity's central funds (specialized investment vehicles used by Fidelity^® funds to invest in particular security types or investment disciplines).

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Risks</b></font>

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market.

• Financial Services Exposure. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations.

• Subsidiary Risk. Investment in an unregistered subsidiary is not subject to the investor protections of the Investment Company Act of 1940 (1940 Act) and is subject to the risks associated with investing in derivatives and commodity-linked investing in general. Changes in tax and other laws could negatively affect investments in the subsidiary.

• Prepayment. The ability of an issuer of a debt security to repay principal prior to a security's maturity can cause greater price volatility if interest rates change.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. A decline in the credit quality of an issuer or a provider of credit support or a maturity-shortening structure for a security can cause the price of a security to decrease.

• Leverage Risk. Leverage can increase market exposure, magnify investment risks, and cause losses to be realized more quickly.

• Commodity-Linked Investing. The value of commodities and commodity-linked investments may be affected by the performance of the overall commodities markets as well as weather, political, tax, and other regulatory and market developments. Commodity-linked investments may be more volatile and less liquid than the underlying commodity, instruments, or measures.

• Commodity Futures. Investments in commodity futures contracts are also subject to the risk of the failure of any of the exchanges on which the fund’s positions trade or of its clearinghouses or counterparties. In addition, certain commodity exchanges limit fluctuations in certain futures contract prices during a single day by regulations referred to as "daily price fluctuation limits" or "daily limits." Under such daily limits, during a single trading day no trades may be executed at prices beyond the daily limit. If triggered, these limits could prevent the fund from liquidating unfavorable positions and subject the fund to losses or prevent it from entering into desired trades during the particular trading day.

In addition, the fund is classified as non-diversified under the Investment Company Act of 1940, which means that it has the ability to invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Performance</b></font>

Performance history will be available for the fund after the fund has been in operation for one calendar year.

[1] The fund may invest in a wholly-owned subsidiary. The subsidiary has entered into a separate contract with Geode Capital Management, LLC (Geode) for the management of its portfolio pursuant to which the subsidiary pays Geode a fee at an annual rate of 0.30% of its net assets. The subsidiary also pays certain other expenses including custody fees. Geode has contractually agreed to waive the fund's management fee in an amount equal to the management fee paid to Geode by the subsidiary. This arrangement will remain in effect for at least one year from the effective date of the prospectus, and will remain in effect thereafter as long as Geode's contract with the subsidiary is in place. If Geode's contract with the subsidiary is terminated, Geode, in its sole discretion, may discontinue the arrangement.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY OXFORD STREET TRUST

Prospectus Date

rr_ProspectusDate

Sep. 29, 2018

07.31 Fidelity Commodity Strategy Fund F PRO-03 | Fidelity® Commodity Strategy Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

<p style="font: bold 20pt Arial, Helvetica, sans-serif;">Fund Summary</p><p style="font: normal 12pt Arial, Helvetica, sans-serif;"><b>Fund/Class</b>:<br/><b>Fidelity® Commodity Strategy Fund</b>/F</p>

Objective [Heading]

rr_ObjectiveHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;">Investment Objective</font>

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks to provide investment returns that correspond to the performance of the commodities market.

Expense [Heading]

rr_ExpenseHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Fee Table</b></font>

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Shareholder fees</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px"></p>

(fees paid directly from your investment)

rr_ShareholderFeeOther

none

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Annual Operating Expenses</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">(expenses that you pay each year as a % of the value of your investment)</p>

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Portfolio Turnover</b></font>

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 0% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

none

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example helps compare the cost of investing in the fund with the cost of investing in other funds.

Let's say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

<p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Sell All Shares</p>

Strategy [Heading]

rr_StrategyHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Strategies</b></font>

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing in commodity-linked derivative instruments, short-term investment-grade debt securities, cash, and cash equivalents.

• Investing up to 25% of assets in a wholly-owned subsidiary organized under the laws of the Cayman Islands that invests in commodity-linked total return swaps based on the value of commodities or commodities indexes and in other commodity-linked derivative instruments.

• Managing the fund to track an index chosen to represent the commodities market, as well as short-term investment-grade debt securities, which as of July 31, 2018 was the Bloomberg Commodity Index Total Return℠.

• Investing in domestic and foreign issuers.

• Engaging in commodity-linked derivatives transactions that have a leveraging effect on the fund.

• Investing in Fidelity's central funds (specialized investment vehicles used by Fidelity^® funds to invest in particular security types or investment disciplines).

Risk [Heading]

rr_RiskHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Risks</b></font>

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market.

• Financial Services Exposure. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations.

• Subsidiary Risk. Investment in an unregistered subsidiary is not subject to the investor protections of the Investment Company Act of 1940 (1940 Act) and is subject to the risks associated with investing in derivatives and commodity-linked investing in general. Changes in tax and other laws could negatively affect investments in the subsidiary.

• Prepayment. The ability of an issuer of a debt security to repay principal prior to a security's maturity can cause greater price volatility if interest rates change.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. A decline in the credit quality of an issuer or a provider of credit support or a maturity-shortening structure for a security can cause the price of a security to decrease.

• Leverage Risk. Leverage can increase market exposure, magnify investment risks, and cause losses to be realized more quickly.

• Commodity-Linked Investing. The value of commodities and commodity-linked investments may be affected by the performance of the overall commodities markets as well as weather, political, tax, and other regulatory and market developments. Commodity-linked investments may be more volatile and less liquid than the underlying commodity, instruments, or measures.

• Commodity Futures. Investments in commodity futures contracts are also subject to the risk of the failure of any of the exchanges on which the fund’s positions trade or of its clearinghouses or counterparties. In addition, certain commodity exchanges limit fluctuations in certain futures contract prices during a single day by regulations referred to as "daily price fluctuation limits" or "daily limits." Under such daily limits, during a single trading day no trades may be executed at prices beyond the daily limit. If triggered, these limits could prevent the fund from liquidating unfavorable positions and subject the fund to losses or prevent it from entering into desired trades during the particular trading day.

In addition, the fund is classified as non-diversified under the Investment Company Act of 1940, which means that it has the ability to invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

Risk Lose Money [Text]

rr_RiskLoseMoney

<font style="FONT-FAMILY: Times New Roman" size="3">You could lose money by investing in the fund.</font>

Risk Nondiversified Status [Text]

rr_RiskNondiversifiedStatus

<font style="FONT-FAMILY: Times New Roman" size="3">In addition, the fund is classified as non-diversified under the Investment Company Act of 1940, which means that it has the ability to invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.</font>

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

<font style="FONT-FAMILY: Times New Roman" size="3">An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.</font>

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Performance</b></font>

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

Performance history will be available for the fund after the fund has been in operation for one calendar year.

Performance One Year or Less [Text]

rr_PerformanceOneYearOrLess

<font style="FONT-FAMILY: Times New Roman" size="3">Performance history will be available for the fund after the fund has been in operation for one calendar year.</font>

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

<font style="FONT-FAMILY: Times New Roman" size="3">www.fidelity.com</font>

07.31 Fidelity Commodity Strategy Fund F PRO-03 | Fidelity® Commodity Strategy Fund | Fidelity Commodity Strategy Fund-Class F Fidelity

Risk/Return:

rr_RiskReturnAbstract

Management fee

rr_ManagementFeesOverAssets

0.40%

Distribution and/or Service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

none

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.05%

^[1]

Total annual operating expenses

rr_ExpensesOverAssets

0.45%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.05%

^[1]

Total annual operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

0.40%

1 year

rr_ExpenseExampleYear01

$ 41

3 years

rr_ExpenseExampleYear03

128

5 years

rr_ExpenseExampleYear05

224

10 years

rr_ExpenseExampleYear10

$ 505

[1] The fund may invest in a wholly-owned subsidiary. The subsidiary has entered into a separate contract with Geode Capital Management, LLC (Geode) for the management of its portfolio pursuant to which the subsidiary pays Geode a fee at an annual rate of 0.30% of its net assets. The subsidiary also pays certain other expenses including custody fees. Geode has contractually agreed to waive the fund's management fee in an amount equal to the management fee paid to Geode by the subsidiary. This arrangement will remain in effect for at least one year from the effective date of the prospectus, and will remain in effect thereafter as long as Geode's contract with the subsidiary is in place. If Geode's contract with the subsidiary is terminated, Geode, in its sole discretion, may discontinue the arrangement.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	FIDELITY OXFORD STREET TRUST
Prospectus Date	rr_ProspectusDate	Sep. 29, 2018
Document Creation Date	dei_DocumentCreationDate	Sep. 27, 2018