The current study is the first to study the role of prosocial behavior in young children's friendships. It was interesting to find, therefore, that highly prosocial children, like antisocial or aggressive children, like to stick together. Importantly, high levels of nominated best friends’ prosocial behavior at T1 were only linked with high levels of prosocial behavior in the target child at T1 when friends’ concomitant levels of antisocial behavior were low. Again, this finding may indicate that divergent sources of social influence compete with each other in their effect on children's behavior.