British voluntary and faith organizations were important components of the rapidly expanding “third sector” of civil society and non-governmental organizations in the post-1945 international system. Many postwar international volunteers had participated in relief efforts for displaced persons during the war. This included the Friends (Quakers) Ambulance Unit (FAU), which operated the Friends Post War Service (FPWS, 1946–48) and the Friends Ambulance Unit International Service (FAUIS, 1948–59). These organizations provided Quaker conscientious objectors with an alternate means of completing their National Service. This chapter evaluates the historical experiences of FPWS/FAUIS volunteers as examples of international service motivated by moral conviction and argues that FPWS/FAUIS relief work constituted a form of private international social governance.