This quantitative study is aimed at exploring the effect of Green Human Resource Management (GHRM) practices on employee Pro-Environmental Behaviors (PEB). Our conceptual model was developed based on the Ability, Motivation, and Opportunity (AMO) framework and the Attitude-Behavior-Context theory (ABC). Our model was tested using data from 696 full-time medical staff working in Vietnamese hospitals. In order to fully understand how GHRM practices, Green knowledge sharing, individual green value, and employee pro-environmental behaviors are related, structural equation modeling is combined with necessary condition analysis. The results indicate that (a) green training and involvement (GRS), green recruitment (GTI), and green performance management and compensation (GPC) positively impact GKS, and (b) GKS is positively related to PEB. The findings also demonstrate that the individual green value plays a moderating role in the connection between GRS, GTI, GPC, and GKS. A discussion is included on how practices within GHRM can stimulate employees to exhibit GKS and PEB, as well as the implications for GHRM theory and practice.