Success of organizational initiatives for environmental sustainability hinges upon employees' proenvironmental behaviors. One of the contemporary important challenges faced by HR professionals is to ensure proper integration of environmental sustainability into human resource policies. The green human resource management (green HRM) has emerged from organizations engaging in practices related to protection of environment and maintaining ecological balance. The aim of this study is to examine the effects of green HRM practices (green recruitment and selection, green training and development, green performance management and appraisal, green reward and compensation, and green empowerment) on employee's proenvironmental behavior. Moreover, this study is going to test the mediating effect of proenvironmental psychological capital and the moderating effect of environmental knowledge on green HRM practices-proenvironmental behavior. Data from 347 employees working in coal generating, power industry, food, chemical, and pharmaceutical industries were collected. Results revealed that green HRM practices positively affected employee's proenvironmental behavior, and proenvironmental psychological capital mediated this link. Employee's environmental knowledge moderated the effect of green HRM practices on proenvironmental behavior. KEYWORDS green empowerment, green HRM, green performance management and appraisal, green recruitment and selection, green reward and compensation, green training and development, proenvironmental behavior, psychological capital