Updated: 11/12/2023 by Computer Hope
Sierra Entertainment logo

Founded in 1979 by Ken Williams and Roberta Williams as On-Line Systems, Sierra is an American video-game developer and publisher. On-Line Systems became Sierra On-Line in 1980, and moved its headquarters from Los Angeles, California, USA to the Sierra foothill community of Oakhurst, California. The company is currently owned by Activision, a subsidiary of Activision Blizzard.

Contact information

Support: (310) 255-2050
Fax: Unknown
TDD/TTY: Unknown
Website: Sierra official website
Activision official website
FTP: Unknown
E-mail: Activision contact page
Address: Activision Publishing, Inc.
3100 Ocean Park Boulevard
Santa Monica, California 90405
Stock: ATVI (Activision Blizzard, Inc.)

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Company news

August 7, 2014 - The Sierra website came back online.

2008 - Activision announced Sierra was closed and up for sale.

October 2007 - Releases Timeshift.

September 2007 - Releases World in Conflict.

2005 - Sierra Entertainment integrated with other companies including High Moon Studios, Massive Entertainment, Radical Entertainment, and Swordfish Studios into its division.

February 19, 2002 - Sierra changed its name to Sierra Entertainment.

March 19, 2001 - The game Tribes 2 went gold.

June 2000 - Sierra became part of Vivendi Universal.

1988 - Sierra Entertainment's Kings Quest IV became first game to support AdLib.

1979 - Sierra was founded.