Given that a strong owner has been identified as an important factor in the success of megaprojects, there has been a growing recognition of the importance of megaproject owner organizational capabilities. However, the questions of what organizational capabilities do owners need to foster successful megaprojects, and whether these capabilities are the stronger the better, have yet to be addressed. To answer these questions, this study identified the dimensions of owner organizational capabilities based on literature and interviews, and developed several sets of parallel hypotheses. Based on the 229 valid questionnaire data collected, the relationships between owner organizational capabilities and megaproject success were analyzed through hierarchical multiple regression, and the results were discussed through expert interviews. The findings show that owner coordination, dynamic, and system integration capabilities have positive impacts on megaproject success, with coordination capabilities being the most significant. While the impact of motivational capabilities on megaproject success is inverted U-shaped. This study provides an actionable dimensional framework for megaproject owner capabilities, moving the field of owner organizational capabilities beyond the conceptual level. This study provides empirical evidence for the importance of megaproject owner organizational capabilities and takes a more dialectical view of a strong owner. The empirical results can provide insights and guidance on the configuration and development of megaproject owner capabilities.