Turtle Rock Studios (formerly Valve South) is an American video game developer founded in March 2002 by Michael Booth. It was acquired by Valve Corporation in 2008, but was re-founded in 2011 as an independent company by Phil Robb and Chris Ashton. Turtle Rock Studios is involved in the creation of original titles as well as the provision of consulting services to the digital entertainment industry.

The company's most notable games are the first Left 4 Dead, which was published by Valve, and Evolve, which was originally set to be published by THQ but was later published by 2K Games. The founder of the company had worked for Westwood Pacific, and assisted in the development of the Counter-Strike series. The company expanded from six employees to more than seventy staff members in 2011 to 2014, and opened a subsidiary company called Turtle Rock Garage in 2011, which specialized in developing casual games.