Architects are facing increasing risks that result from heightened expectations of benefits and performance when designing green buildings compared to traditional buildings. This study aims to explore the possible risk factors for architects in green building projects in South Korea and assess risk mitigation measures. To attain this goal, 14 risk factors and 12 mitigation measures were determined through an extensive literature review. A questionnaire was administered to architects practicing green building design and criticality index was employed to assess major risk factors and mitigation measures. This study identified ‘adoption of new technology and process’, ‘green building certification results’, ‘building products and materials’, and ‘energy saving uncertainty’ as the major risk factors of green building projects. Additionally, the questionnaire proposed ‘contract indicating each party’s role, liability, and limitations clearly’, ‘utilizing integrated design process’, and ‘understanding client’s goal in green building projects’ as the three most effective risk mitigation measures in designing green buildings. There are few studies that focus on architects’ perceived risks concerning green building projects; this study contributes to a deeper knowledge and attempts to fill the current literature gap, which would beneft South Korea’s green building design practice by aiding in the development of better risk management strategies.