G.I. Williamson (born 1925) is a Reformed theologian, pastor, and author. Williamson is retired after fifty years in Christian ministry. After serving in the army and working as a dance hall musician, Williamson converted to Christianity at age 21. He attended Hope College in Holland, Michigan for one year and then transferred to Drake University in Des Moines, Iowa. He graduated from Drake in 1949. In 1952, he earned a B.D. from Pittsburgh-Xenia Theological Seminary under John Gerstner.