The extent to which current theories on family-related factors associated with children's depression and conduct problems are applicable to Mexican American children was examined among demographically comparable samples of low-income Mexican American (English and Spanish speaking) and Euro-American mothers and children. There were ethnic differences in mean levels of children's depression, maternal inconsistent discipline, and hostile control. In addition, there were differences across language within the Mexican American sample on levels of reported maternal inconsistent discipline and hostile control. The vast majority of relations between parenting and mental health were similar between Mexican Americans and Euro-Americans, suggesting that current theories do apply across ethnic groups. However, analyses across language within the Mexican American sample showed that language preference moderated the relation between maternal acceptance and children's conduct problems. Moreover, the relation between acceptance and hostile control differed across groups. These results are discussed in light of the relative influence of ethnicity and other contextual variables on parenting and children's mental health.