Women play key roles in fish value chains, especially post-harvest processing and marketing of fish products. However, gendered inequities in small-scale fishery value chains persist around the globe, limiting livelihood benefits for many women and their households. This study uses a mixed methods approach to investigate how gender norms shape gendered inequities in marketing margins for fish retailers in small-scale fishery value chains. In the empirical case of usipa (Engraulicypris sardella) trade in Malawi, we find that there is nearly equal participation in fish retail between females and males. Yet, there is a statistically significant difference in marketing margins between female and male usipa retailers, with female retailers earning less. We find that gender norms indirectly impact marketing margins by disproportionately constraining time for women, shaping household decision-making regarding women’s spending, limiting women’s access to resources including financial services and fish, and maintaining patriarchal power dynamics. Despite these results, we find that there remains a dominant discourse among men that gender does not impact marketing margins. In connecting specific gender norms, revealed through qualitative methods, to specific livelihood outcomes, measured through quantitative methods, this study provides new insight into gendered inequities in small-scale fish trade.