This study examined spillover between daily family stressors and school problems among 589 ninth-grade students (mean age = 14.9 years) from Mexican, Chinese, and European backgrounds. Spillover was examined using a daily diary methodology in which adolescents reported on their school and family experiences each day for 2 weeks. Analyses using hierarchical linear modeling revealed reciprocal spillover effects between adolescents’ daily functioning in the family and school domains that spanned several days. Longitudinal analyses indicated that spillover between family stressors and school problems also occurs across the high school years, from 9th to 12th grade, and that both are predictive of poorer academic performance in 12th grade. These findings have practical implications for adolescents’ academic achievement trajectories and general well-being.