Joseph Houldsworth Oldham CBE (1874–1969), known as J. H. or Joe, was a Scottish missionary in India, who became a significant figure in Christian ecumenism, though never ordained in the United Free Church as he had wished.

The World Council of Churches (WCC) is a worldwide Christian inter-church organization founded in 1948 to work for the cause of ecumenism. Its full members today include the Assyrian Church of the East, the Oriental Orthodox Churches, most jurisdictions of the Eastern Orthodox Church, the Union of Utrecht, the Lutheran World Federation, the Anglican Communion, the Mennonite churches, the World Methodist Council, the Baptist World Alliance, the World Communion of Reformed Churches, the Pentecostal churches, the Moravian Church and the Malankara Mar Thoma Syrian Church. Notably, the Catholic Church is not a full member, although it sends delegates to meetings who have observer status.