Sexual minority youth are at risk for negative school-based experiences and poor academic outcomes. Yet, little is known about their experiences in positive school-based contexts. Using the "National Longitudinal Study of Adolescent Health" (1,214 sexual minority and 11,427 heterosexual participants), this study compared participation rates in, predictors of, and outcomes associated with three types of school-based extracurricular activities--sports, arts, and school clubs--by sexual orientation and gender. Findings revealed several significant sexual orientation and gender differences in participation rates in school-based sports, clubs, and arts activities. Furthermore, findings suggested that the outcomes associated with extracurricular activity involvement do not differ by sexual orientation and gender; however, predictors of participation in these domains varied across groups. (Contains 5 tables and 1 figure.)