The promotion of Green Buildings (GB) has become a global trend that improves resource efficiency and the well-being of societies. The development of GB still encounters different obstacles in developing countries. The critical success factors of GB and their relationships with GB certification levels in Thailand have been investigated. The relationships between the competence of individual project participants and competence of project team at different GB certification levels are also analyzed. The results reveal the underlying patterns of the overall picture of the GB industry in Thailand, and suggest that all project participants should continuously improve their competences via technical and management innovation for delivering affordable and sustainable products, thereby making green buildings more available and appealing to the public. This study provides empirical evidence for all project participants to adopt appropriate team building strategies and optimally allocate their resources to achieve the suitable GB certification levels.