Collectivists know themselves better than individualists do, in that collectivists provide more accurate self-predictions of future behavior in situations with moral or altruistic overtones. In 3 studies, respondents from individualist cultures overestimated the likelihood that they would act generously in situations involving redistributing a reward (Study 1), donating money (Study 2), or avoiding rude behavior (Study 3), whereas collectivists were, in general, more accurate in their self-predictions. Both groups were roughly accurate in predicting the behavior of their peers. Collectivists were more accurate in their self-predictions than were individualists, even when both groups were sampled from the same cultural group (Study 4). Discussion centers on culturally specific motivations that may bias the accuracy of self-insight and social insight.