Game harmony describes how harmonious (nonconflictual) or disharmonious (conflictual) the interests of players are in a game, as embodied in the game’s raw payoffs. It departs from the traditional game-theoretic approach in that it is a nonequilibrium behavioral approach that can be psychologically founded. The authors experimentally test the predictive power of basic game harmony measures on a variety of well-known 2 × 2 games and randomly generated 2 × 2 and 3 × 3 generic games. The findings support its all-rounded predictive power. Game harmony provides an alternative tool that is both powerful and parsimonious, as it does not require information on a player’s degree of rationality, social preferences, beliefs, and perceptions.