Extant researchresearchresearch on the linkage between perceived organizational support for the environmentperceived organizational support for the environment (POSE) and hotel employee green behavioremployee green behavior (EGB) in the workplaceworkplace, especially studies that investigate the boundary conditions of this effect, is very limited. Using social exchange theorysocial exchange theory, this study aims to fill this researchresearch gap. Data were collected from a two-wave survey of 316 four- and five-star hotel employees in Vietnam, and structural equation modeling (SEM) was applied to analyze the data. The findings show that, in addition to being an important driver of hotel EGB, POSE also significantly influences it through employee green passiongreen passion. Furthermore, employees’ collectivist orientationemployees’ collectivist orientation constitutes a boundary condition that enhances the effect of employee green passiongreen passion on hotel EGB. This researchresearch extends existing literature on the POSE–EGB relationship by explicating both mediation and moderation effects and provides managerial implicationsimplications for promoting EGB.