The review includes a critical analysis of studies that examined the effects of acculturation on the mental health and well-being of Latino adolescents. Recent findings that have documented the association between acculturation and substance abuse among Latino adolescents are discussed. The article also examines the dearth of research on the role of acculturation in the substance-abusing behaviors of African-American adolescents. The authors maintain that understanding the effects of acculturation on these behaviors could begin to explain why African-American adolescent substance abuse rates have been historically lower than those of European-American and Latino adolescents. Also included is an examination of research on the role of acculturation in treatment outcomes of Latino and African-American adolescents. Theoretical models of substance-abusing behaviors in African-American and Latino adolescents need to be expanded to incorporate the effects of acculturation into their explanatory matrix. These models should be multidimensional and multidirectional to reflect the true nature of the acculturation process. Moreover, because of the wide range of ethnic differences within these populations, models must be constructed with flexible components that depict the acculturation processes that are relevant to the particular African-American or Latino subgroups being studied. Finally, in order to provide information that can be used by policymakers and health care practitioners for prevention programs, models should include an evaluation of the acculturation process from both an asset and risk-based perspective. 44 references