UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q/A

(Amendment No. 1)

For the Quarterly Period Ended June 30, 2011

OR

For the Transition Period From              to             

Commission File Number: 001-07260

Nortel Networks Corporation

(Exact name of registrant as specified in its charter)

Registrant’s Telephone Number Including Area Code (905) 863-7000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer”, “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

Indicate the number of shares outstanding of each of the issuer’s classes of common stock as of June 30, 2011.

498,206,366 shares of common stock without nominal or par value

Explanatory Note

Nortel Networks Corporation is filing this Amendment No. 1 (the “Form 10-Q/A”) to its Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2011 (the “Form 10-Q”), filed with the U.S. Securities and Exchange Commission on August 11, 2011, for the sole purpose of furnishing the Interactive Data File as Exhibit 101 in accordance with Rule 405 of Regulation S-T. As permitted by Rule 405(a)(2)(ii) of Regulation S-T, Exhibit 101 was required to be furnished by amendment within 30 days of the original filing date of the Form 10-Q.

No other changes have been made to the Form 10-Q. This Form 10-Q/A continues to speak as of the original filing date of the Form 10-Q, does not reflect events that may have occurred subsequent to the original filing date, and does not modify or update any related disclosures made in the Form 10-Q.

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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 thereunto duly authorized.

NORTEL NETWORKS CORPORATION

(Registrant)

Date: September 9, 2011

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