This brief has key messages through anexperiment in Uganda, we find that empowering adolescentgirls triggers a surge in their brothers’competitiveness.Understanding preferences for competition isimportant because competitiveness is a predictor of labormarket outcomes. To examine gender differences in preferencefor competition, the World Bank’s Africa GenderInnovationLab, in collaboration with researchers from the Universityof Maryland and ColumbiaUniversity, launched alab-in-the-field experiment within a randomized controltrial of BRAC’scommunity-based Empowerment and Livelihoodfor Adolescents (ELA) program in Uganda.The ELA programsimultaneously provided vocational and life skills trainingfor girls aged 14 to 20. An impact evaluation of ELA showedthat it empowered girls along economic and socialdimensions: the program increased girls’ participation inself employment, improved girls’ control over their bodies,and shifted deep rooted gender norms held by adolescentgirls in communities that participated in the program. Fouryears after the implementation began, we used alab-in-the-field experiment to compare communities thatreceived ELA with those that did not. The aim of thisexperiment was to test whether girl’s empowerment would havea direct impact on girls’ or boys’ competitiveness. Tomeasure preferences for competition, we implemented theexperimental protocol of Niederle and Vesterlund (2007).More specifically, participants were asked to select acompensation scheme before performing a simple task, fromwhich we identified their taste to compete. They eitherchose to be paid according to a competitive tournamentscheme or a non competitive piece-rate scheme. Theexperiment was designed to control for a host of factorssuch as individual differences in ability, overconfidence,risk aversion, and altruism. Our findings highlight theimpact of gender equality on gender differences incompetitiveness: when boys are faced with more empoweredsisters, they increase their competitiveness. This suggeststhat the benefits of adolescent girls’ empowerment programsmay spill over beyond the participating girls themselves totheir brothers. More work needs to be done to understand ifthe changed behavior in brothers will have persistenteffects on girls in the future.