Purpose: This study aims to envisage the impact of green project management (GPM) practices on sustainable competitive advantage (SCA). Moreover, this study also accessed the mediating role of green knowledge acquisition (GKA) as a mechanism between GPM and SCA. Design/methodology/approach: Using a quantitative field survey, the data were collected from the multi-sector manufacturing enterprises (n = 265) in Pakistan. The measurement and structural model were tested through Analysis of Moment Structure by conducting a covariance structure analysis. Findings: The findings suggest that GPM practices are positively related to SCA. In addition to this direct effect, GKA play a significant role in explaining the associations between GPM practices and SCA. The findings bring essential insights for the enterprises, policymakers, practitioners and project managers to promote GPM practices for low-carbon projects to achieve SCA. Research limitations/implications: The data used in this study is cross-sectional in nature. The geographic location is limited to firms in Pakistan, while well-validated subjective measures are used to make the survey more convenient for participants. Practical implications: The practitioners in general, while project managers in particular, are recommended to implement GPM practices and GKA to achieve high performance of SCA. Originality/value: To the best of the authors’ knowledge, this is one of the first studies to examine GPM practices and its effect on SCA directly and via GKA in a single model.