Riverbed Technology (RVBD)

(Addresses, including zip code, and telephone numbers, including area code, of principal executive offices)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

On September 26, 2006, Riverbed Technology, Inc. entered into an Agreement of Sublease (the “Sublease”) with PricewaterhouseCoopers LLP (“Sublessor”) for office space at 199 Fremont Street, San Francisco, California (the “Premises”). Riverbed intends to use the Premises as its new corporate headquarters. The size of the Premises is approximately 63,798 square feet. The term of the sublease runs from February 1, 2007 to August 30, 2010. The aggregate minimum lease commitment is $5.1 million. The Sublease also calls for additional payments for electricity and a portion of real estate taxes and operating expenses. Riverbed will provide Sublessor with a letter of credit equal to $1,400,000 to serve as the security deposit for the Sublease and Sublessor has provided Riverbed with a tenant improvement allowance of up to $1,275,960. The Sublease is conditioned on the written consent of the landlord, GLL Fremont Street Partners.

The summary above is not intended to be complete and is qualified in its entirety by reference to the complete text of the Agreement of Sublease attached hereto as Exhibit 10.1 and incorporated herein by reference.

The information set forth in Item 1.01 above is incorporated by reference herein.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

(Addresses, including zip code, and telephone numbers, including area code, of principal executive offices)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

On September 26, 2006, Riverbed Technology, Inc. closed the initial public offering of shares of its common stock. Riverbed sold 9,990,321 shares of common stock, which number of shares included the underwriters’ exercise in full of their option to purchase up to 1,290,321 shares to cover over-allotments, and 100,000 shares of common stock were sold by the selling stockholder named in Riverbed’s Registration Statement on Form S-1 (File No. 333-133437).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.