We evaluate the long-run effects of an intervention in India that engaged adolescent girls and boys in classroom discussions about gender equality for two years during secondary school, aiming to reduce their support for societal norms that restrict women’s and girls’ opportunities. In prior work, we found that the program made attitudes more supportive of gender equality. In this follow-up study, we estimate longer-run effects, when the study participants are, on average, 20 years old. We also surveyed younger siblings and parents to assess spillover effects of the intervention. First, we find no effects of the intervention on female participants' educational attainment, employment, or age of marriage. Second, the effect on gender attitudes is still present but attenuated compared to the shorter-run effect. Third, female participants report having more personal autonomy. Fourth, we find sizeable spillovers to younger siblings: siblings of those in the treatment group have more progressive gender attitudes. Finally, we find evidence of upward spillovers from boys who participated in the program to their fathers, whose gender attitudes become more progressive.