PurposeThe study aims to investigate the relationships between green intellectual capital, green human resource management (HRM), and sustainability.Design/methodology/approachThe research is based on information gathered from 112 large Malaysian manufacturing companies.FindingsThe study findings revealed that green human capital and green relational capital positively influence green HRM. In addition, green HRM positively related to social, environmental and economic performance. Besides, green HRM positively mediates the relationships between green human capital and economic, social and environmental performance. Finally, green relational capital improves sustainability (economic, environmental, and social performance) mediated by green HRM.Originality/valueThe current study contributes to the literature by examining green IC (green human capital, green structural capital, and green relational capital) as an independent variable and green HRM as a mediating variable for sustainability (economic, environmental, and social performance). The findings and recommended for the managers of large manufacturing firms and practitioners to invest in green IC to achieve sustainability through green HRM.