Walter George Muelder (March 1, 1907 in Boody, Illinois – June 12, 2004) was an important American social ethicist, ecumenist and public theologian. He studied under Edgar S Brightman at Boston University and began his teaching career at Berea College and the University of Southern California. He served as Dean of Boston University School of Theology from 1945 to 1972, and was known as the "Red Dean" because of his socialist and pacifist leanings.
As a theologian he helped develop Boston School of Personalism into a Christian social ethic at a time when social ethics was still a relatively new term. As an ecumenist he was involved in forming early social statements of the World Council of Churches. During his tenure at Boston University, he was responsible for the training of more African American PhD students than any single university in the country. He was credited by Martin Luther King Jr., a student of his at Boston (as well as Coretta Scott King in later years), as being an important influence in Dr. King's pilgrimage to nonviolence as a philosophy of social change. Among his major works are Foundations of the Responsible Society (1959) and Moral Law and Christian Ethics (1966).