Half-Life is a science fiction action film series based on Valve Software's acclaimed video game series of the same name, which are produced by Lambda Entertainment and distributed by Valve Films. It began with the first film Half-Life: The Movie (2006), which was followed by a three part miniseries titled Half-Life: The Series. Although plans for more sequels were made, the film series was put on hold due to the creation of the Half-Life 2 prequel television series City 17 Street, which aired from 22 August 2006 to 6 July 2018.

Following the cancellation of City 17 Street, the film series was revived, with the announcement of new projects including Half-Life: The Freeman (2018), G-Man (2019), and Half-Life: Seven Hour War (2020), with it being unofficially rebranded as the "Half-Life Cinematic Universe". More projects including television shows and shorts are also in early production.