This longitudinal study examined the intergenerational gap in acculturation, subsequent conflict, and their mental health consequences in Southeast Asian American adolescents. It was hypothesized that perceived intergenerational discrepancy in acculturation during early adolescence would predict intergenerational conflict in late adolescence, which, in turn, would increase depressive symptomatology in late adolescence. Using data from the Children of Immigrants Longitudinal Study (A. Portes & R. G. Rumbaut, 2001; R. G. Rumbaut, 1994), 490 Southeast Asian American adolescents in 8th and 9th grades completed surveys and again 3 years later. The results supported the hypothesis and showed that intergenerational/intercultural conflict fully mediated the longitudinal effect of perceived intergenerational discrepancy in acculturation on depressive symptomatology. Recommendations for community- based interventions for both parents and youth are offered.