The implementation of China’s mega-strategy the Belt and Road Initiative (BRI) in Southeast Asia is premised on a solid economic foundation, part of which is the activity of entrepreneurs of the Chinese origin in those countries. Although extant studies offer explanations of the BRI implementation in Southeast Asia, as well as of the performance of ethnic Chinese entrepreneurs in those countries, they have fallen short of developing an integrated research approach to the role of ethnic Chinese businessmen in making the foundations of the BRI in Southeast Asia long-term and sustainable. The article analyses the place of Southeast Asia in the PRC’s BRI priorities, substantiated by Beijing’s support for entrepreneurial associations embracing businesspersons of the Chinese origin in Southeast Asian states, as well as main features of Chinese companies in those countries and Chinese practices of making and maintaining commercial contacts. In the author’s view, although the BRI expansion in Southeast Asia has become self-maintaining and self-reproducing, in the years to come, the PRC’s commercial practices will have to be partially adopted to expectations of Southeast Asian business community, mostly, ethnic Chinese entrepreneurs.