This paper studies the link between self-image and behavior among those who face stigma due to poverty and social exclusion. Using a randomized eld experiment with sex workers in Kolkata (India), we examine whether a psychological intervention aimed at mitigating the adverse e ects of internalized stigma can induce behavior change. We nd signi cant improvements in participants' self-image, as well as their savings and preventive health choices. Additionally, changes in savings and health behavior persist up to fteen and months later respectively. Our ndings highlight the potential of purely psychological interventions to improve the life choices and outcomes of marginalized groups.