Donald Allen Crosby (born 7 April 1932) is an American theologian who is professor emeritus of philosophy at Colorado State University, since January 2000.

During the first two years of his doctoral work he served as part-time assistant minister at the First Congregational Church on the Green in Norwalk, Connecticut.

In addition, Crosby’s exposure to the field of world religions at Columbia helped to broaden his thought far beyond its earlier religious conservatism.

The God is Dead movement in the 1960s, and especially its reflections on theological implications of the atrocities of the Nazi regime and the carnage of World War II, had an important influence on his abandonment of traditional theism.

He has been strongly influenced by the thought of William James, John Dewey, Alfred North Whitehead, and Paul Tillich in doing so, but other great philosophical and religious thinkers of the Western tradition have made their decisive contributions to his outlook as well, as have important writers about Eastern ways of thinking and living.

Still another major influence on Crosby’s outlook is the findings of contemporary science, especially in the fields of cosmology, evolutionary biology, and ecology.