Building sector is the largest source of greenhouse gas emissions around the globe. Being green, or sustainable, is one pressing issue coming from both internal and external drivers for construction and engineering companies. Green building has experienced rapid growth in the past several years. To assess how green, or sustainable, the building is, several green rating systems have been ... [Show full abstract] developed. Among these rating systems, more similarities exist than differences. One noteworthy difference-project management-serves as the motivation behind this investigation. To identify the role of project management that is less related to technology and engineering in developing green building rating systems, this research centers on a comparison between the LEED, the Green Globes, and the BCA Green Mark to obtain an understanding of current practices, and more importantly, to address the significance of project management in achieving green or sustainable construction. The findings suggest that project management adopted in green building construction involves both the practice and the process. Although the practice-mainly represented through the project management body of knowledge-is currently the focus of green building construction, the importance of the process, such as managing people, organizational structure, building commissioning, performance documentation, and so on, cannot be neglected, as can be seen from the evolution of the green rating systems. It is recommended that the construction and engineering companies take project management in terms of both the process and the practice into consideration when fulfilling requirements of being green.