Game harmony is a generic game property that describes how harmonious (non-conflictual) or disharmonious (conflictual) the interests of players are, as embodied in the payoffs. Pure coordination games are games of complete harmony,and constant-sum games are games of pure disharmony: the majority of games is somewhere in the middle. This paper provides measures of game harmony that can be used to classify normal form games, and analyzes their properties. Game harmony is positively associated with cooperation, and we review evidence that this is so. Framing effects increasing cooperation may work by increasing perceived game harmony.