In combinatorial game theory, a game is partisan or partizan if it is not impartial. That is, some moves are available to one player and not to the other.

Most games are partisan; for example in chess, only one player can move the white pieces.

Partisan games are more difficult to analyze than impartial games, as the Sprague-Grundy theorem does not apply. However, the application of combinatorial game theory to partisan games allows the significance of numbers as games to be seen, in a way that is not possible with impartial games.