Purpose– The purpose of this paper is to explore the role of specific human resource management (HRM) practices in the implementation of environmental initiatives in terms of their impact on employee attitudes to the organization and to its environmental programme.Design/methodology/approach– The study used a mixed method approach comprising a survey of 675 employees and 16 semi-structured interviews undertaken across two organizations.Findings– Survey data, analysed using path analysis, showed that participation in environmental initiatives is directly associated with higher levels of employee engagement with the organization, higher rating of their organization’s environmental performance, and lower intention to quit. The qualitative study supports the quantitative data, also highlighting other aspects of environmental initiatives that may affect employee attitudes.Research limitations/implications– Future study should either collect longitudinal data or rely on data collected from two waves of data collection. Objective performance data should also be collected in order to better understand the causal effect of HRM on environmental performance.Practical implications– Our findings have implications for the business case for sustainability, providing some evidence that implementing environmental initiatives with HRM support may not only motivate staff around environmental programmes but may provide wider benefits for organizations in terms of overall job satisfaction and employee retention.Social implications– Successful implementation of environmental management initiatives have both organizational and employee level outcomes. Employees who were more aligned with their organizational environmental objectives were found to be more engaged and less likely to quit.Originality/value– This study provided both quantitative and qualitative empirical evidence to support the importance of integrating the HRM function into the implementation of environmental initiatives.