The present dissertation examines the influence of self-involvement with perpetrators and victims on third-party reactions to deviants. Dealing with others’ social behaviors regulates social life and successful cooperation between interaction partners. Third-party reactions to deviants are sensitive to group context, and thereby more likely to protect ingroup interests. Such biased reactions raise the question of how much they are triggered by involvement (i.e., shared group membership, empathy) with perpetrators or victims of deviance. Three reported lines of research extend the current knowledge on cognitive (memory), emotional (anger), and behavioral (punishment) reactions to deviance within and between social groups. Research Line I examined whether accurate memory for persons’ social behavior is group-specific. The reported studies show that deviant ingroup members are remembered better than other ingroup and outgroup members (uncooperative or cheating). Guessing behavior indicates that participants assumed more cooperative ingroup members than outgroup members. Research Line II investigated whether involvement with victims is crucial for anger about deviance. Results show that the wrongfulness (i.e., perpetrator’s intentions) elicits more anger than the harmfulness (i.e., consequences for a cared-for-other) of deviance. Research Line III examined how involvement with perpetrators or victims influences anger and punishment of deviance. Anger and (altruistic) punishment emerge consistently as responses to unfairness, even in outgroup interactions. Negative reactions to ingroup perpetrators and victims varies with the contextual settings of the studies. Taken together, memory, anger, and punishment are sensitive to perpetrators’ and victims’ group memberships, and also emerge irrespective of self-involvement. The discussion addresses how such reactions facilitate social life and cooperation in groups.