This study examined distorted self- and peer perceptions in aggressive and nonaggressive boys at preadolescent and early adolescent age levels. Subjects completed semantic differential ratings of themselves and of their peer partners following two brief dyadic discussion tasks with competitive inductions and a game-playing task with a cooperative induction. Subjects also rated their expectations for self- and peer behavior prior to the two competitive interaction tasks. Research assistants later rated videotapes of the interactions. Aggressive boys had more distorted perceptions of dyadic behavior as they overperceived aggression in their partners and underperceived their own aggressiveness. These distorted perceptions of aggression carried over for aggressive boys into the third interaction task with a cooperative induction, indicating these boys' difficulty in modulating these perceptions when the overt demand for conflict is no longer present in the situation. Results also indicated that aggressive boys' perceptions of their own behavior after the first interaction task is substantially affected by their prior expectations, in comparison to nonaggressive boys who rely more on their actual behavior to form their perceptions.