Because anger in close relationships is not only a source of strain, but can also serve to further emotional competence, a questionnaire was constructed on nine strategies of anger regulation within a same-sex friendship (SAR). A factor analysis of the children's version resulted in four factors. A confirmatory factor analysis corroborated the comparability of the factor structures of the children's and the adolescents' version of the SAR. Results of a 5-year longitudinal study suggest that participants tended to use negotiation more frequently as adolescents than as children. Aggressive and distancing strategies declined in adolescence. Results are discussed under the perspective that learning to manage conflicts of interest and anger without resorting to hostility (or avoidance) is a social task in friendship.