An emerging literature suggests that the increasingly complex family histories of American children are linked with multiple domains of adolescent development. Much of this scholarship focuses on associations at the individual level. Here, the authors consider whether key dimensions of the school context, specifically the aggregate level of family instability and the academic press within schools, moderate the link between family instability and young people's course-taking patterns in mathematics in high school. Using the school-based design and the retrospective reports of family structure in the National Longitudinal Study of Adolescent Health and the linked academic transcript data in the Adolescent Health and Achievement Study (n = 6,545), the authors find that students from unstable families do more poorly when they attend schools with a high proportion of academically oriented students. The prevalence of family instability in a school does not moderate the individual experience of family instability in predicting course-taking patterns. (Contains 3 tables and 2 figures.)