Within the framework of stage-environment fit theory, the authors examined the contribution of family relations to adolescent outcomes concurrently and longitudinally, as well as the moderating effects of gender and ethnicity in these associations. Data came from a longitudinal study of European American and African American families from a range of socioeconomic backgrounds. Results demonstrated that gender and ethnicity influenced both the level and rate of change in family relations and adolescent outcomes. Family relations contributed either concurrently or longitudinally to at least 1 of the adolescent outcomes. The effects of gender and ethnic moderation differed according to both the time frame and the outcome assessed.