Psychosocial engagement of adopted adolescents was examined as a function of longitudinal patterns of stability and change in parents'perceptions of the compatibility of the child within the family. Psychosocial engagement involves the adolescent's active use of his or her inner resources to interact positively with others in family, peer, and community contexts. Participants included 177 adoptive families who were interviewed when the target child was in middle childhood and again when the child was in adolescence. Five patterns of stability and change in compatibility were identified. Parents' perceptions of their adolescent's social competence were related to patterns indicating higher compatibility, and higher reports of problem behaviors were found in families with patterns indicating lower compatibility. The same pattern of results was evident whether mothers' or fathers' scores for social competence and behavior problems were used. No main effects for adolescent gender or interaction between gender and change pattern emerged.