This article contributes to the historiography on human rights and (religious) internationalism by tracing how the ecumenical movement in the post-war decades sought to protect the religious freedom of its co-religionists in Catholic and Muslim countries, specifically Italy, Nigeria, and Indonesia. In co-operation with local actors, the Commission of the Churches on International Affairs sought to anchor international human rights in the domestic sphere through constitutional provisions. These activities constituted a significant strand of Christian human rights engagement from the 1940s to the 1960s, which intersected with the Cold War and decolonisation. The article then contrasts this with the turn to a more pluralistic and communitarian conception of human rights in the 1970s, animated by liberation theologies. As the World Council of Churches embraced a ‘revolutionary’ tradition and worked to resist military dictatorships, racism, and global inequality, it gravitated towards Marxism-inflected and anticolonial strands of human rights discourse