The material dimensions of China's Belt and Road Initiative (BRI), which encompass multibillion-dollar investments in transport infrastructure and industrial estates, are expected to make China a key player in the development and increasing integration of mainland Southeast Asia. This article, however, looks beyond trade and hard infrastructure to examine China's emerging efforts to build influence at the ideational level through the use of Buddhism as a cultural resource. It documents government-sponsored outreach to Southeast Asia's Buddhist leaders and communities in Thailand, Myanmar, Cambodia and Laos. It finds that there has been a surge in outreach from a range of Chinese provinces since the advent of the BRI in 2013. These outreach efforts warrant categorization as influence operations because they are orchestrated through the offices of the United Front Work Department, are being used to promote China's political goals, and are sanctioned by a party that remains staunchly atheist and forbids its members to practise religion. In broader terms, China's use of Buddhism as an adjunct to the BRI in mainland Southeast Asia suggests it is seeking to dampen disquiet about the BRI, including by fostering a sense of shared values with mainland Southeast Asian states.