This study examines how cultural contexts shape the relationship between female parliamentarians and environmental sustainability. Drawing on institutional theory, we argue that the impact of women in parliament on environmental outcomes depends on the cultural environment in which they operate. Using data from 18 countries over 20 years, we apply robust econometric techniques, including two-stage ordinary least square (2SLS), system-generalise method of moments (S-GMM), instrumental variable generalized method of moments (IV-GMM), and ordinary least squares (OLS), and use green growth to measure environmental sustainability. Our findings reveal that female parliamentarians positively influence environmental sustainability in countries with a long-term orientation and individualist cultures. However, cultural factors such as power distance, masculinity, and uncertainty avoidance limit their impact. This study advances the debate on the female leadership-environmental nexus by highlighting the role of culture. The results imply that, beyond appointing women, countries must cultivate cultural support to maximize their contributions to environmental sustainability.