To investigate social exclusion, 146 dyads of close friends (N292, ages 10, 12, and 14) were observed as they played a board game with a same-gender confederate actor, trained to be a difficult play partner. Verbalizations and gestures were coded for verbal and nonverbal social exclusion, verbal aggression, and verbal assertion. The results indicated few developmental differences. For verbal responses in the presence of the actor, boys were more socially exclusive and verbally aggressive than were girls. Girls engaged in more nonverbal social exclusion in the presence of the actor than did boys. Girls' socially exclusive behaviors were unrelated to other negative behaviors and more strongly related between friends in the actor's absence.