Results indicated Mexican-American youth who were oriented to Mexican culture showed a significant increase in family cohesion during mid-adolescence. These Mexican-American adolescents tended to come from intact families and have the least educated parents, who were mainly born in Mexico. No significant gender differences emerged. In terms of family cohesion, Mexicans who were oriented to American culture were not significantly different from Euro-American adolescents, who tended to display reductions in family cohesion over time. The findings suggest that there are small differences in family cohesion that correspond to aspects of the family life cycle, such as the stages of adolescent development. The findings also strongly support the notion that ethnicity and cultural orientation impact family cohesion patterns. Future research should examine cultural process variations within large ethnic groups due to the potential for variation in the cultural domains under consideration. Participants were 4,156 adolescents from grades six, seven, and eight who were recruited from 5 school districts in a large metropolitan area. Participants were assessed at three time points during three consecutive years using survey instruments administered during class hours. Survey instruments measured parental education (SES), cultural orientation, and family cohesion. Ethnic differences in family cohesion were tested using hierarchical linear regression models. Tables, figure, references