To behave in a socially responsible manner and to support the concepts of sustainable development, organizations apply various processes and activities for greening their business. In addition to green marketing, supply and distribution chain, production, packaging and recycling, green human resources management (GHRM) also plays a big role. For this purpose, organizations incorporate a green component into all human resources management (HRM) phases, thereby building a green employer brand. This paper examines the extent to which organizations in Serbia and Bosnia and Herzegovina apply GHRM activities and practices, and whether there are differences in the application of these practices depending on the size and business sector. Empirical research carried out in Serbia and Bosnia and Herzegovina has found that green activities and HRM practices are applied to a small extent, with slightly higher results achieved by small and manufacturing organizations. The findings indicate the need for greater engagement of organizations to strengthen the awareness of the importance of GHRM, support their sustainable development and strengthen the brand in domestic and foreign markets.