Counter-Strike is a tactical first-person shooter game developed by Valve. It was initially developed and released as a Half-Life modification by Minh "Gooseman" Le and Jess Cliffe in 1999, before Le and Cliffe were hired and the game's intellectual property acquired. Counter-Strike was released by Valve for Microsoft Windows in November 2000, and is the first installment in the Counter-Strike series. Several remakes and ports were released on Xbox, as well as OS X and Linux.

Tactical shooter is a sub-genre of first- and third-person shooters, associated with using strategy, planning, and tactics in gameplay, as well as the realistic simulations of ballistics, firearm mechanics, physics, stamina, and low time to kill. Dating back to strategy games from the late 1980s, the genre first rose to prominence in the late 1990s with the releases of several well-received tactical shooters. The popularity of the genre saw a decline in the late 2000s as fast-paced "arcade"-like action shooters rose to prominence, it has seen a revitalization since the mid-2010s with the successful releases of several modern tactical shooters.