AbstractFrom 1958 to 1965, J. E. Lesslie Newbigin worked for the International Missionary Council and then the World Council of Churches, specifically leading the integration of the organizations. Newbigin had a profound impact on the importance and role of mission within the ecumenical movement during the early transition of decolonialism around the globe. This article will reflect upon the history, contribution, and legacy of Newbigin in the conversation of mission in the ecumenical movement, specifically the World Council of Churches Commission on World Mission and Evangelism and the International Review of Mission. This reflection comes at the 25‐year mark since Newbigin's death and addresses part of Newbigin's legacy that recent books, The Church and Its Vocation and Becoming a Missionary Church, could only briefly discuss.