We investigated the effect of participating in two domains of extracurricular activities (sports and performance arts/clubs) in Grades 7 and 8 on Grade 9 academic motivation and letter grades, above baseline performance. Participants were 483 students (55% male; 33% Euro-American, 25% African American, and 39% Latino). Propensity score weighting controlled for potential confounders in all analyses. Delayed (Grade 8 only) and continuous participation (Grades 7 and 8) in sports predicted competence beliefs and valuing education; delayed and continuous participation in performance arts/clubs predicted teacher-rated engagement and letter grades. Benefits of participation were similar across gender and ethnicity; however, Latino youth were least likely to participate in extracurricular activities. Implications for reducing ethnic and income disparities in educational attainment are discussed.