Abstract: This study of 175 Mexican-origin families examined a mediational model linking the linguistic acculturation of mothers and adolescents with a wide array of family mediators and adolescent mental health outcomes. Family linguistic acculturation, a latent construct based on maternal and adolescent acculturation, was positively related to increased family and interparental conflict but was not related to maternal parenting practices. Family conflict mediated the link between acculturation and two adolescent outcomes, conduct problems and depressive symptoms. Family acculturation showed a complex pattern of positive, indirect (mediated) and negative, direct effects on adolescent depressive symptoms. Findings are discussed in relation to traditional cultural values of Mexican heritage families and prevailing theories about why more acculturated Mexican-origin youth are at increased risk for problem behaviors.