This study examines the impact of environmental management training (EV_MT) on firms’ capacity for eco-innovation and how executive gender diversity (Ex_mgd), measured as the percentage of female executives, moderates this relationship. Drawing on Upper-Echelons and Natural Resource–Based perspectives, we analyze a 15-year panel of 5155 firm-year observations from 952 publicly listed European companies (2010–2024). Using a two-step system-GMM estimator to address endogeneity from lagged dependent variables and reverse causality, we control for firm size, asset tangibility, leverage, and environmental disclosure. Our findings reveal that EV_MT has a robust, positive effect on Environmental Innovation Scores (EV_Inno), with structured training programs yielding immediate gains and fostering long-term capability development. Contrary to expectations, the interaction between EV_MT and Ex_mgd is negative and significant, indicating that higher proportions of female executives, in the absence of coordinated governance mechanisms, may attenuate the training–innovation link. However, the main effect of Ex_mgd remains modestly positive, suggesting that gender diversity alone supports eco-innovation. These results highlight the importance of aligning green training initiatives with inclusive leadership processes and clear coordination protocols to fully realize sustainability objectives. By unpacking the internal mechanisms and boundary conditions of eco-innovation, this study offers actionable insights for managers and policymakers seeking to design effective human-capital and governance strategies that drive resilient, future-ready organizations.