We study gender differences in the impacts of competition and subjective feedback, using an online game with pop-up texts and graphics as treatments. We define 8 groups: players see a Top 10 leaderboard or not (competitiveness), and within these, they receive no feedback, supportive feedback, rewarding feedback, or „trash talk” (feedback type). Based on 5191 participants, we find that competition only increases the performance of males. However, when it is combined with supportive feedback, the performance of females also increases. This points to individualized feedback as a potential tool for decreasing gender gaps in competitive settings such as STEM fields.