In recent years, green building has attracted wide attention from both academia and industry. As green building projects are inevitably plagued with risks, this study attempted to assess the risks in green building projects in Singapore. Categorizing a list of 28 risk factors into 11 groups, the study performed a questionnaire survey and received 31 responses from project managers in Singapore. A risk assessment model was developed using the fuzzy synthetic evaluation approach. Using the proposed model, the likelihood of occurrence, magnitude of impact and risk criticality of each risk factor, group and the overall risk were calculated. “Inaccurate cost estimation” was the top risk factor, and “cost overrun risk” was the most critical risk group. The overall risk criticality was high, implying risk management was still necessary for green construction in Singapore. The proposed risk assessment model is reliable and practical for professionals in the green building industry, and can be applied in risk assessment in other countries. As few studies focused on risks in green projects, this study expands the knowledge and literature.