This paper evaluates an intervention in India that engaged adolescent girls and boys in classroom discussions about gender equality for two years, aiming to reduce their support for societal norms that restrict women’s and girls’ opportunities. Using a randomized controlled trial, we find that the program made attitudes more supportive of gender equality by 0.18 standard deviations, or, equivalently, converted 16% of regressive attitudes. When we resurveyed study participants two years after the intervention had ended, the effects had persisted. The program also led to more gender-equal self-reported behavior, and we find weak evidence that it affected two revealed-preference measures.