Purpose – This study aims to investigate how psychological green climate (PGC), green organisational citizenship behaviour (GOCB) and green self-efficacy (GSE) play a role in the relationship between green human resource management (GHRM) and environmental performance (EP) in healthcare organisations. Design/methodology/approach – The research has applied a quantitative research method using partial least squares structural equation modelling to test the hypotheses from a conceptual framework derived from the literature. The research collected data from 509 employees (managerial and non-managerial) from healthcare organisations in Bangladesh employing a cross-sectional survey using two steps of non-probability sampling, i.e. purposive sampling and convenience sampling for data collection through a self-administered questionnaire. Findings – The findings from this research are three-fold. Firstly, GHRM does not have a direct effect on EP. Secondly, PGC and GOCB partially and sequentially mediate between GHRM and EP. Thirdly, GSE and GOCB partially and sequentially mediate between GHRM and the EP of healthcare organisations. Practical implications – The study makes recommendations for healthcare managers and policymakers with regards ensuring environmental sustainability focusing on the employee’s behaviour and psychological factors. As the healthcare sector is a service provider to a variety of stakeholders in Bangladesh, ultimately this study contributes to society and the country as a whole. Originality/value – The study contributes to the sustainability literature relating to healthcare organisations, applying social cognitive theory and the norm activation model to underpin the role PGC, GSE and GOCB play individually and collectively to improve EP through GHRM implementation.