For the 2000 game,see Counter-Strike (video game).
For other uses, see Counterstrike.

Counter-Strike (CS) is a series of multiplayer first-person shooter video games, in which teams of terrorists and counter-terrorists battle to, respectively, perpetrate an act of terror (bombing, hostage-taking) and prevent it (bomb defusal, hostage rescue). The series began on Windows in 1999 with the first version of Counter-Strike. It was initially released as a modification for Half-Life and designed by Minh "Gooseman" Le and Jess "Cliffe" Cliffe, before the rights to the game's intellectual property were acquired by Valve Corporation, the developers of Half-Life.

Counter-Strike:Condition Zero, developed by Turtle Rock Studios and released in 2004. Later that same year, Counter-Strike: Source was released by Valve. Released only eight months after Counter-Strike: Condition Zero, in November 2004, the game was a remake of the original Counter-Strike and the first in the series to run on Valve's newly created Source engine. The fourth game in the main series to have been developed by Valve, Counter-Strike: Global Offensive, was released in 2012 for Windows, OS X, Xbox 360, and PlayStation 3. Hidden Path Entertainment, who also worked on Counter-Strike: Source post-release, helped to develop the game alongside Valve. There have been several community made "spin off" titles created over the years.

Counter-Strike is an objective-based, multiplayer first-person shooter. Two opposing teams—the Terrorists and the Counter Terrorists—compete in game modes to complete objectives, such as securing a location to plant or defuse a bomb and rescuing or guarding hostages. At the end of each round, players are rewarded based on their individual performance with in-game currency to spend on more powerful weapons in subsequent rounds. Winning rounds results in more money than losing, and completing objectives such as killing enemy players gives cash bonuses. Uncooperative actions, such as killing teammates, results in a penalty.