The objective of this study is to evaluate how the implementation of green human resource management (HRM) practices affects environmental performance and explore the role of sustainability-focused employee behavior in mediating the connection between green HRM practices and environmental performance in Bangladesh. To achieve this, a conceptual model was formulated based on the theoretical foundations of the Ability, Motivation, and Opportunity theory and the Research-Based View theory. The model was examined using the partial least squares structural equation modeling (PLS-SEM) approach with SmartPLS v4.0. Primary data was gathered from 310 employees across various organizations in Bangladesh. The findings demonstrate that both green recruitment and selection processes, along with the green compensation and reward system, have a positive influence on environmental performance. Furthermore, sustainability-oriented employee behavior was identified as a partial mediator in this relationship. However, this study reveals that there is no direct or indirect correlation between green training and development programs, as well as the green performance appraisal system, and environmental performance. Based on these results, it is recommended that green training and development initiatives, as well as performance appraisal systems, be strengthened in Bangladesh to foster greater employee involvement in environmentally friendly practices. This study contributes practical insights to improve HR policies, which can subsequently lead to enhanced environmental performance. Keywords: Green HRM practices, Sustainability, Employee, Behavior, Environment, and Performance.