PurposeDrawing on the social exchange theory (SET) and the self-determination theory (SDT), the present study aims to examine the impact of green human resource management (GHRM) on three types of employee green behavior (EGB) – green in-role, innovative and extra-role – in the presence of environmental managerial support (EMS) as a conditional factor.Design/methodology/approachThe research model was verified based on data from 419 respondents employed in companies operating in the energy sector in Poland (Europe’s “coal heartland”). PLS-SEM was used in the statistical analyses.FindingsThis study shows that GHRM positively impacts three types of EGB. EMS positively moderates the relationships of GHRM with both green extra-role behaviors and innovative work behaviors; however, EMS does not play a moderating role in the relationship between GHRM and green in-role behaviors.Originality/valueThis study, being one of a kind, enriches the literature by exploring the conditional role of EMS on the integrated relationship of GHRM practices with in-role, extra-role and innovative behaviors and offers evidence from the rarely examined energy sector, which plays a vital role in the transformation of nations toward sustainable development.