In this field experiment, we took a novel approach to building empathy among early adolescents in four schools (n = 857), targeting the motivation to empathize rather than addressing the ability to empathize. Students who received a norms-based intervention, compared to those in other conditions—experienced greater motivation to empathize, which indirectly affected their prosocial behavior as reported by peers. Findings suggest a novel avenue for increasing empathy among adolescents—by focusing on peer-driven motivation—and underscore the importance of context in shaping intervention outcomes.