Treyarch is an American video game developer company, founded in 1996 and acquired by Activision in 2001. Treyarch is located in Santa Monica, California.

Treyarch has developed several games in the Call of Dutyseries, which are listed below. Call of Duty 3 and Call of Duty: World at War have been set in the WWII timeframe,Call of Duty: Black Ops is set in the 1960s. Unlike Infinity Ward, Treyarch has developed games outside of the Call of Duty franchise, and traditionally makes Nintendo Wii versions of their games.

Some of Treyarch's Call of Duty team comes from an older studio known as Gray Matter Interactive, responsible for games like Kingpin (while under their old name "Xatrix") and Return to Castle Wolfenstein. The team was responsible for developing Call of Duty: United Offensive before merging with Treyarch. Some of the Gray Matter team still resides at Treyarch, although its founder and several executives from the former studio have found employment elsewhere.

Treyarch is sometimes referred to as Call of Duty's "B-Team", since the Call of Duty games that they made in the past weren't as successful as those made by Infinity Ward up until the release of Black Ops. Treyarch's latest game, Call of Duty: Black Ops, was released on November 9th, 2010.