Since the 1980s, Singapore has experienced the widespread use of international construction joint ventures (ICJVs), which are associated with a variety of risks. This study aims to assess the risks associated with the underground rail ICJVs in Singapore. To achieve this objective, a comprehensive literature review was carried out and a questionnaire survey was conducted with 33 contractors. The survey results reported “disagreement on some conditions in contract” as the most critical risk. Although the risk criticalities of some risks significantly differed according to multiple company characteristics, there was strong agreement on the risk rankings. With the help of this study, ICJV partners can identify the most critical risks and thus develop mitigation measures. Also, the findings from this study provide a comprehensive picture of risks for the companies that intend to participate in ICJVs in Singapore.