Exhibit 15

November 14, 2006

Wyndham Worldwide Corporation

Seven Sylvan Way

Parsippany, New Jersey

We have made reviews, in accordance with the standards of the Public Company Accounting Oversight Board (United States), of the unaudited interim financial information of Wyndham Worldwide Corporation and subsidiaries (the “Company”), for the three and nine-month periods ended September 30, 2006 and 2005, as indicated in our report dated November 14, 2006 (which report included an explanatory paragraph related to the fact that, prior to its separation from Cendant Corporation (“Cendant”), Wyndham Worldwide Businesses of Cendant Corporation was comprised of the assets and liabilities used in managing and operating the lodging, vacation exchange and rental and vacation ownership businesses of Cendant as discussed in Note 1 to the interim condensed consolidated and combined financial statements; that included in Note 14 of the interim condensed consolidated and combined financial statements is a summary of transactions with related parties; and that also as discussed in Note 1 to the interim condensed consolidated and combined financial statements the Company adopted the provisions for accounting for real estate time-sharing transactions as of January 1, 2006); because we did not perform an audit, we expressed no opinion on that information.

We are aware that our report referred to above, which is included in your Quarterly Report on Form 10-Q for the quarter ended September 30, 2006, is incorporated by reference in Wyndham Worldwide Corporation’s Registration Statement No. 333-136090 on Form S-8.

We also are aware that the aforementioned report, pursuant to Rule 436(c) under the Securities Act of 1933, is not considered a part of the Registration Statements prepared or certified by an accountant or a report prepared or certified by an accountant within the meaning of Sections 7 and 11 of that Act.

/s/ Deloitte & Touche LLP

Parsippany, New Jersey

* * *