Religious differences are often portrayed as a source of conflict and tension in development work. Such portrayals imply that faith-based organizations (FBOs) struggle to bridge religious divides and construct co-ownership when engaging in multi-religious contexts. This article nuances this view through a study of how Christian FBOs are working with antitrafficking programs in Buddhist South-East Asia. Drawing on interviews and observations in Thailand and Cambodia, the analysis demonstrates that differences in religion need not present an obstacle to the construction of co-ownership. In contrast, a shared religious ontology between FBOs and local stakeholders and beneficiaries facilitates a shared understanding of the problem of human trafficking and the solutions to address it. This indicates that religion can be a resource, rather than a problem, in establishing co-ownership with local actors in the antitrafficking work of the FBOs. However, in interactions with secular antitrafficking actors, finding common ground is more challenging: the secular-religious divide seems wider than the Christian–Buddhist divide. The article thus provides important insights for scholars, policymakers and practitioners by nuancing assumptions about the role of religion in development in multi-religious contexts. Western secularism may in fact present a more significant obstacle than an explicit religious identity when seeking to construct co-ownership with local communities in Buddhist South-East Asia.