Turtle Rock Studios, Inc. is game developer founded by Michael Booth in March 2002. They are most well-known for their work on the Counter-Strike franchise, having ported the game to the Xbox, developed Counter-Strike: Condition Zero, and creating various maps as updates to Counter-Strike: Source. Turtle Rock's best known work is the PC version of the original Left 4 Dead.
On January 10, 2008, Valve Corporation announced that they had acquired Turtle Rock Studios, Inc. Turtle Rock Studios, Inc. was briefly known internally as Valve South, as the Valve Corporation headquarters is located in Bellevue, Washington and Turtle Rock Studios, Inc. is located in Los Angeles, California. Later in 2008, Valve shut down Turtle Rock Studios and offered its employees to relocate to Valve proper. In 2009, Turtle Rock was re-opened by Chris Ashton and Phil Robb. They are no longer associated with Valve.
In May 2011, Turtle Rock announced they were working on a new title running on CryEngine 3, to be published by THQ. During THQ's bankruptcy proceedings, it was revealed that this game is Evolve, a co-op FPS, and the new publisher will be Take-Two.
On December 17th 2021 it was announced that Tencent had aquired the studio.