This study evaluates gender gaps in the collateral requirements of bank loans using a sample of firms in Latin America. We measure firm-level gender composition through ownership and workforce, both of which are directly related to women's economic empowerment. Additionally, we evaluate the differences in the impacts of firms' gender composition on collateral borrowing between banks that adopt sustainable finance codes of conduct and those that do not. Our empirical findings indicate that female-dominant firms are less likely to be required to provide collateral for their bank loans, and when collateral is required, its value is relatively lower. However, banks adopting sustainable finance codes are not less likely to grant collateral loans to female-dominant firms; in fact, these banks even require greater collateral values from these firms. The implications derived from our empirical findings concern gender inequality in accessing financial credit in developing countries and underscore the need for designing sustainable finance codes that specifically consider and rectify the challenges faced by female-owned firms, especially by firms with a majority female workforce.