This study critically examines the mediating role of employees’ eco-friendly behavior (EFB) and the moderating role of green organizational support (GOS) within the relationship between green human resource management (GHRM) and environmental performance (EP) in Turkey’s hospitality sector. As the global hospitality industry grapples with its significant environmental footprint, this research addresses an acute need for empirically grounded insights into how organizational strategies and employee behaviors can be leveraged to achieve sustainability objectives. The study draws on primary data collected from 346 employees across multiple five-star hotels in Turkey. Data collection was facilitated through structured surveys, and analysis employed confirmatory factor analysis and structural equation modeling. Results provide evidence for EFB’s mediating role and GOS’s moderating effects. Findings underscore the need for comprehensive GHRM strategies synergized with robust GOS systems to foster employee commitment to sustainability goals.