Extreme Networks, Inc. is an American networking company based in Morrisville, North Carolina. Extreme Networks designs, develops, and manufactures wired and wireless network infrastructure equipment and develops the software for network management, policy, analytics, security and access controls.

Extreme Networks was established by co-founders Gordon Stitt, Herb Schneider, and Stephen Haddock in 1996 in California, United States, with its first offices located in Cupertino, which later moved to Santa Clara, and later to San Jose. Early investors included Norwest Venture Partners, AVI Capital Management, Trinity Ventures, and Kleiner Perkins Caufield & Byers. Gordon Stitt was a co-founder and served as chief executive officer until August 2006, when he retired and became chairman of the board of directors.

The initial public offering in April 1999 was listed on the NASDAQ stock exchange as ticker "EXTR."

In April 2013, Charles W. Berger (from ParAccel as it was acquired by Actian) replaced Oscar Rodriguez as CEO.

On April 19, 2015, Charles W. Berger resigned as CEO, and was replaced by Board Chairman Ed Meyercord.

In October 1996, Extreme Networks acquired Mammoth Technology.

Extreme Networks acquired Optranet in February 2001 and Webstacks in March 2001. Extreme had invested in both companies, which were purchased for about $73 million and $74 million respectively.

On September 12, 2013, Extreme Networks announced it would acquire Enterasys Networks for about $180 million.