In this dissertation, I examine the phenomenon of immigration and how intercultural contact affects both immigrants and natives through acculturation and enculturation processes. I center on three main sources of individual differences in the outcomes of acculturation and enculturation: a) ethnicity, b) genetic plasticity, and c) immigrant generation. To examine these three sources, I employed data from a sample of Asian (n = 1584) and Latino (n = 3525) adolescents from the National Longitudinal Study of Adolescent Health, who were assessed in four waves from ages 12-16 to ages 24-32. I found some group differences between Asians and Latinos, evidence of Gene-Culture correlations, and partial support for generational differences. These findings are discussed using a Cultural Development and Psychopathology framework (Causadias, 2013).