We conducted a randomized controlled trial of a 5-month resilience-based program (Girls First Resilience Curriculum or RC) among 2308 rural adolescent girls at 57 government schools in Bihar, India. Local women with at least a 10th grade education served as group facilitators. Girls receiving RC improved more (vs. controls) on emotional resilience, self efficacy, social-emotional assets, psychological wellbeing, and social wellbeing. Effects were not detected on depression. There was a small, statistically significant negative effect on anxiety (though not likely clinically significant). Results suggest psychosocial assets and wellbeing can be improved for girls in high-poverty, rural schools through a brief schoolday program. To our knowledge, this is one of the largest developing country trials of a resilience-based school-day curriculum for adolescents.