Social exclusion of those who challenge group norms was investigated by asking children and adolescents, adolescents, age 9–13 years (N = 381), to evaluate exclusion of group members who deviated from group norms. Testing predictions from social reasoning developmental theories of group-based exclusion, children and adolescents evaluated exclusion based on group norms involving allocation of resources and group traditions about dress code. Exclusion of deviant members was viewed as increasingly wrong with age, but also varied by the type of norm the deviant challenged. Participants who reported disliking a deviant member who wanted to distribute money unequally also found it acceptable to exclude them. Those who disliked deviants who went against norms about dress codes did not think exclusion was warranted. These findings are discussed in the context of children's social-cognitive development regarding peer rejection as well as the role played by moral judgment and group dynamics.