Sven Co-op (usually abbreviated as SC) is a cooperative game multiplayer modification for the first-person shooter computer game Half-Life, where players must work together against AI controlled enemies (NPCs), solve puzzles and complete other objectives (usually specified in a MOTD) as a team.

The game was originally created and released by Daniel 'Sven Viking' Fearon as a small mod with two single player maps and the game configured to allow NPCs in the game (by changing a CVAR to allow them to exist in the multiplayer game mode). Sven Co-op was released on January 19, 1999 - before Valve's Team Fortress Classic - and is therefore the oldest Half-Life mod in existence that is still in development. It has since grown to become a full blown mod, with a full team, and one of the most played games on Steam as of September 18, 2006, excluding the official games by Valve.