While Christianity remains marginal in Southeast Asia, recent social science scholarship has drawn attention to the nonetheless substantial influence of Christian Non-Governmental Organisations in the region. Though not a homogeneous group of actors, these organisations share in common that they ground their work in Christian values and convey these values through their activities. Their margin of manoeuvre is constrained by the specific national contexts in which they operate and is marked by these contexts’ past experiences with Christian envoys. In this chapter, I will first provide some insights into the variety of Christian NGOs working in the region and into the diverging influences they exert on political norms; from contesting dominant values, to reinforcing them. I will then rely on ethnographic research to explore how one specific Christian NGO operates to shape Southeast Asian policies, examining which norms it promotes, but also where it draws the limits of its advocacy.