Background: Adolescent participation in pro-social activities such as sport can promote identity formation, self-efficacy and social support, but its benefits in India remain unassessed. We examined longitudinal effects of adolescent sport participation on economic, social and political engagement, marital health and family planning among young adults in India. Methods: We analyzed prospective data from unmarried adolescents (n = 2,322, ages 15À19) who participated in the Youth in India 2007À8 study (wave 1) and were followed in the UDAYA study 2015À16 (wave 2), in Bihar, India. Sport participation was assessed in wave 1. Outcomes assessed in wave 2 were economic engagement (vocational training, past year paid employment), social group participation, political participation, marriage (any and prior to 18), and among those married, marital violence [MV] and contraceptive use. We used logistic and multinomial models to assess longitudinal associations between sport and our outcomes, adjusting for age, residence and wealth at baseline and secondary schooling completion at follow-up. Results: In multivariate models for males, adolescent sport participation was associated with higher odds of vocational training [AOR: 1.92, 95% CI: 1.17, 3.15], social program engagement [AOR: 1.89, 95% CI: 1.14, 3.15], and a trend effect for political participation [AOR: 1.47, 95% CI: 0.97, 2.24]. Among females, sport in adolescence was associated with lower child marriage [ARRR = 0.67, 95% CI: 0.48, 0.96], and higher vocational training [AOR = 1.28, 95% CI: 1.03, 1.16] and family planning use [AOR = 1.31, 95% CI: 1.05, 1.63]. Crude effects were noted for delayed marriage, paid work and perpetration of marital violence among males. Interpretation: Evidence from India shows that sport can be an instrument supporting pro-social engagement for boys and girls. Further understanding of the gendered nature of sport and the mechanisms linking sport to agency among youth is needed.