UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

Information Statement Pursuant to Rules 13d-1 and 13d-2

Under the Securities Exchange Act of 1934

(Amendment No.     )*

Zai Lab Limited

(Name of Issuer)

Ordinary Shares, par value $0.00006 per share

(Title of Class of Securities)

98887Q104**

(CUSIP Number)

December 31, 2017

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this schedule is filed:

☐ Rule 13d-1(b)

☐ Rule 13d-1(c)

☒ Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

** This CUSIP number applies to the Issuer’s American depositary shares, each representing one Ordinary Share.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 98887Q104 SCHEDULE 13G Page 2 of 13 Pages

1	NAME OF REPORTING PERSON SEQUOIA CAPITAL CV IV HOLDCO, LTD. (“SC CV IV HOLDCO”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)  ☐        (b)  ☐
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION CAYMAN ISLANDS
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 2,986,278
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 2,986,278
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,986,278
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 6.1%1
12	TYPE OF REPORTING PERSON OO

¹  Based on a total of 49,305,903 shares outstanding following completion of the Issuer’s initial public offering, as reported in the Issuer’s prospectus filed with the Securities and Exchange Commission on September 21, 2017.

CUSIP No. 98887Q104 SCHEDULE 13G Page 3 of 13 Pages

1	NAME OF REPORTING PERSON SEQUOIA CAPITAL CHINA VENTURE FUND IV, L.P. (“SC CVF IV”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)  ☐        (b)  ☐
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION CAYMAN ISLANDS
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 2,986,278 shares, of which 2,986,278 shares are directly owned by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV.
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 2,986,278 shares, of which 2,986,278 shares are directly owned by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV.
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,986,278
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 6.1%1
12	TYPE OF REPORTING PERSON PN

¹  Based on a total of 49,305,903 shares outstanding following completion of the Issuer’s initial public offering, as reported in the Issuer’s prospectus filed with the Securities and Exchange Commission on September 21, 2017.

CUSIP No. 98887Q104 SCHEDULE 13G Page 4 of 13 Pages

1	NAME OF REPORTING PERSON SC CHINA VENTURE IV MANAGEMENT, L.P. (“SC CV IV MGMT”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)  ☐        (b)  ☐
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION CAYMAN ISLANDS
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 2,986,278 shares, of which 2,986,278 shares are directly owned by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV. SC CV IV MGMT is the General Partner of SC CVF IV.
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 2,986,278 shares, of which 2,986,278 shares are directly owned by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV. SC CV IV MGMT is the General Partner of SC CVF IV.
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,986,278
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 6.1%1
12	TYPE OF REPORTING PERSON PN

¹  Based on a total of 49,305,903 shares outstanding following completion of the Issuer’s initial public offering, as reported in the Issuer’s prospectus filed with the Securities and Exchange Commission on September 21, 2017.

CUSIP No. 98887Q104 SCHEDULE 13G Page 5 of 13 Pages

1	NAME OF REPORTING PERSON SCC GROWTH I HOLDCO A, LTD. (“SCCGI HOLDCO A”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)  ☐        (b)  ☐
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION CAYMAN ISLANDS
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 897,874
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 897,874
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 897,874
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 1.8%1
12	TYPE OF REPORTING PERSON OO

¹ Based on a total of 49,305,903 shares outstanding following completion of the Issuer’s initial public offering, as reported in the Issuer’s prospectus filed with the Securities and Exchange Commission on September 21, 2017.

CUSIP No. 98887Q104 SCHEDULE 13G Page 6 of 13 Pages

1	NAME OF REPORTING PERSON SEQUOIA CAPITAL CHINA GROWTH FUND I, LP (“SC CGF I”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)  ☐        (b)  ☐
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION CAYMAN ISLANDS
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 897,874 shares, of which 897,874 shares are directly owned by SCCGI HOLDCO A. SCCGI HOLDCO A is wholly owned by SC CGF I.
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 897,874 shares, of which 897,874 shares are directly owned by SCCGI HOLDCO A. SCCGI HOLDCO A is wholly owned by SC CGF I.
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 897,874
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 1.8%1
12	TYPE OF REPORTING PERSON PN

¹  Based on a total of 49,305,903 shares outstanding following completion of the Issuer’s initial public offering, as reported in the Issuer’s prospectus filed with the Securities and Exchange Commission on September 21, 2017.

CUSIP No. 98887Q104 SCHEDULE 13G Page 7 of 13 Pages

1	NAME OF REPORTING PERSON SEQUOIA CAPITAL CHINA GROWTH FUND MANAGEMENT I, L.P. (“SCC GF MGMT I”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)  ☐        (b)  ☐
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION CAYMAN ISLANDS
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 897,874 shares, of which 897,874 shares are directly held by SCCGI HOLDCO A. SCCGI HOLDCO A is wholly owned by SC CGF I. SCC GF MGMT I is the General Partner of SC CGF I.
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 897,874 shares, of which 897,874 shares are directly held by SCCGI HOLDCO A. SCCGI HOLDCO A is wholly owned by SC CGF I. SCC GF MGMT I is the General Partner of SC CGF I.
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 897,874
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 1.8%1
12	TYPE OF REPORTING PERSON PN

¹ Based on a total of 49,305,903 shares outstanding following completion of the Issuer’s initial public offering, as reported in the Issuer’s prospectus filed with the Securities and Exchange Commission on September 21, 2017.

CUSIP No. 98887Q104 SCHEDULE 13G Page 8 of 13 Pages

1	NAME OF REPORTING PERSON SC CHINA HOLDING LIMITED (“SCC HOLD”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)  ☐        (b)  ☐
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION CAYMAN ISLANDS
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 3,884,152 shares, of which 897,874 shares are directly held by SCCGI HOLDCO A and 2,986,278 shares are directly held by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV. SC CV IV MGMT is the General Partner of SC CVF IV. SCCGI HOLDCO A is wholly owned by SC CGF I. SCC GF MGMT I is the General Partner of SC CGF I. SCC HOLD is the General Partner of SC CV IV MGMT and SCC GF MGMT I.
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 3,884,152 shares, of which 897,874 shares are directly held by SCCGI HOLDCO A and 2,986,278 shares are directly held by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV. SC CV IV MGMT is the General Partner of SC CVF IV. SCCGI HOLDCO A is wholly owned by SC CGF I. SCC GF MGMT I is the General Partner of SC CGF I. SCC HOLD is the General Partner of SC CV IV MGMT and SCC GF MGMT I.
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,884,152
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 7.9%1
12	TYPE OF REPORTING PERSON OO

¹ Based on a total of 49,305,903 shares outstanding following completion of the Issuer’s initial public offering, as reported in the Issuer’s prospectus filed with the Securities and Exchange Commission on September 21, 2017.

CUSIP No. 98887Q104 SCHEDULE 13G Page 9 of 13 Pages

1	NAME OF REPORTING PERSON SNP CHINA ENTERPRISES LIMITED (“SNP”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)  ☐        (b)  ☐
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION BRITISH VIRGIN ISLANDS
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 3,884,152 shares, of which 897,874 shares are directly held by SCCGI HOLDCO A and 2,986,278 shares are directly held by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV. SC CV IV MGMT is the General Partner of SC CVF IV. SCCGI HOLDCO A is wholly owned by SC CGF I. SCC GF MGMT I is the General Partner of SC CGF I. SCC HOLD is the General Partner of SC CV IV MGMT and SCC GF MGMT I. SCC HOLD is wholly owned by SNP.
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 3,884,152 shares, of which 897,874 shares are directly held by SCCGI HOLDCO A and 2,986,278 shares are directly held by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV. SC CV IV MGMT is the General Partner of SC CVF IV. SCCGI HOLDCO A is wholly owned by SC CGF I. SCC GF MGMT I is the General Partner of SC CGF I. SCC HOLD is the General Partner of SC CV IV MGMT and SCC GF MGMT I. SCC HOLD is wholly owned by SNP.
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,884,152
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 7.9%1
12	TYPE OF REPORTING PERSON OO

¹ Based on a total of 49,305,903 shares outstanding following completion of the Issuer’s initial public offering, as reported in the Issuer’s prospectus filed with the Securities and Exchange Commission on September 21, 2017.

CUSIP No. 98887Q104 SCHEDULE 13G Page 10 of 13 Pages

1	NAME OF REPORTING PERSON NEIL NANPENG SHEN (“NS”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)  ☐        (b)  ☐
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION HONG KONG SAR
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 0
		6	SHARED VOTING POWER 3,884,152 shares, of which 897,874 shares are directly held by SCCGI HOLDCO A and 2,986,278 shares are directly held by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV. SC CV IV MGMT is the General Partner of SC CVF IV. SCCGI HOLDCO A is wholly owned by SC CGF I. SCC GF MGMT I is the General Partner of SC CGF I. SCC HOLD is the General Partner of SC CV IV MGMT and SCC GF MGMT I. SCC HOLD is wholly owned by SNP. NS wholly owns SNP.
		7	SOLE DISPOSITIVE POWER 0
		8	SHARED DISPOSITIVE POWER 3,884,152 shares, of which 897,874 shares are directly held by SCCGI HOLDCO A and 2,986,278 shares are directly held by SC CV IV HOLDCO. SC CV IV HOLDCO is wholly owned by SC CVF IV. SC CV IV MGMT is the General Partner of SC CVF IV. SCCGI HOLDCO A is wholly owned by SC CGF I. SCC GF MGMT I is the General Partner of SC CGF I. SCC HOLD is the General Partner of SC CV IV MGMT and SCC GF MGMT I. SCC HOLD is wholly owned by SNP. NS wholly owns SNP.
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,884,152
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 7.9%1
12	TYPE OF REPORTING PERSON IN

¹ Based on a total of 49,305,903 shares outstanding following completion of the Issuer’s initial public offering, as reported in the Issuer’s prospectus filed with the Securities and Exchange Commission on September 21, 2017.

CUSIP No. 98887Q104 SCHEDULE 13G Page 11 of 13 Pages

ITEM 1.

(a) Name of Issuer:

        Zai Lab Limited

(b) Address of Issuer’s Principal Executive Offices:

        4560 Jinke Road,

        Bldg. 1, 4F,

        Pudong, Shanghai, China 201210

ITEM 2.

(a) Name of Persons Filing:

        Sequoia Capital CV IV Holdco, Ltd.

        Sequoia Capital China Venture Fund IV, L.P.

        SC China Venture IV Management, L.P.

        SCC Growth I Holdco A, Ltd.

        Sequoia Capital China Growth Fund I, LP

        Sequoia Capital China Growth Fund Management I, L.P.

        SC China Holding Limited

        SNP China Enterprises Limited

        Neil Nanpeng Shen

SC CV IV HOLDCO is wholly owned by SC CVF IV. SC CV IV MGMT is the General Partner of SC CVF IV. SCCGI HOLDCO A is wholly owned by SC CGF I. SCC GF MGMT I is the General Partner of SC CGF I. The General Partner of SC CV IV MGMT and SCC GF MGMT I is SCC HOLD. SCC HOLD is wholly owned by SNP, a company wholly owned by NS.

(b) Address of Principal Business Office or, if none, Residence:

        2800 Sand Hill Road, Suite 101

        Menlo Park, CA 94025

(c) Citizenship:

SC CV IV HOLDCO, SC CVF IV, SC CV IV MGMT, SCCGI HOLDCO A, SC CGF I, SCC GF MGMT I, SCC HOLD: Cayman Islands

        SNP: British Virgin Islands

        NS: Hong Kong SAR

(d) CUSIP Number:

        98887Q104

ITEM 3.

If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

NOT APPLICABLE

ITEM 4. OWNERSHIP

SEE ROWS 5 THROUGH 11 OF COVER PAGES

ITEM 5. OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following   ☐.

ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON

NOT APPLICABLE

CUSIP No. 98887Q104 SCHEDULE 13G Page 12 of 13 Pages

ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.

NOT APPLICABLE

ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.

NOT APPLICABLE

ITEM 9. NOTICE OF DISSOLUTION OF GROUP.

NOT APPLICABLE

ITEM 10. CERTIFICATION

NOT APPLICABLE

CUSIP No. 98887Q104 SCHEDULE 13G Page 13 of 13 Pages

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: February 14, 2018

Sequoia Capital CV IV Holdco, Ltd.
By:	Sequoia Capital China Venture Fund IV, L.P.
	its Sole Member
By:	SC China Venture IV Management, L.P.
	its General Partner
By:	SC China Holding Limited
	its General Partner
By:	/s/ Neil Nanpeng Shen
	Neil Nanpeng Shen, Authorized Signatory
Sequoia Capital China Venture Fund IV, L.P.
By:	SC China Venture IV Management, L.P.
	its General Partner
By:	SC China Holding Limited its General Partner
By:	/s/ Neil Nanpeng Shen
	Neil Nanpeng Shen, Authorized Signatory
SC China Venture IV Management, L.P.
By:	SC China Holding Limited its General Partner
By:	/s/ Neil Nanpeng Shen
	Neil Nanpeng Shen, Authorized Signatory
SCC Growth I Holdco A, Ltd.
By:	Sequoia Capital China Growth Fund I, LP
	its Sole Member
By:	Sequoia Capital China Growth Fund Management I, L.P.
	its General Partner
By:	SC China Holding Limited its General Partner
By:	/s/ Neil Nanpeng Shen
	Neil Nanpeng Shen, Authorized Signatory
Sequoia Capital China Growth Fund I, LP
By:	Sequoia Capital China Growth Fund Management I, L.P.
	its General Partner
By:	SC China Holding Limited its General Partner
By:	/s/ Neil Nanpeng Shen
	Neil Nanpeng Shen, Authorized Signatory
Sequoia Capital China Growth Fund Management I, L.P.
By:	SC China Holding Limited
	its General Partner
By:	/s/ Neil Nanpeng Shen
	Neil Nanpeng Shen, Authorized Signatory
SC China Holding Limited
By:	/s/ Neil Nanpeng Shen
	Neil Nanpeng Shen, Authorized Signatory
SNP China Enterprises Limited
By:	/s/ Neil Nanpeng Shen
	Neil Nanpeng Shen, Authorized Signatory
Neil Nanpeng Shen
By:	/s/ Neil Nanpeng Shen
	Neil Nanpeng Shen