John Hassler Dietrich (1878–1957) was a Unitarian minister, born at Chambersburg, Pa., who advocated Religious Humanism. He was educated at Franklin and Marshall College and at the Reformed Theological Seminary in Lancaster, Pa. He was ordained in the ministry of the Reformed Church in 1905, but before this he held various various positions such as private secretary and manager of Life's Fresh Air Fund. From 1905 to 1916, he held various pastorates, becoming in the latter year pastor of the First Unitarian Society in Minneapolis. He was the author of:
He is considered by some to be the "Father of Religious Humanism" (Olds 1996).