Thomas Jefferson Smull (September 22, 1875 – February 15, 1962) was an American professor of engineering, athletics administrator, athlete, and coach. He was the head football coach at Ohio Northern University in 1905, 1910 and 1918. A member of the faculty at Ohio Northern from 1905 to 1942, he was also the faculty manager of athletics and was known as the school's "father of athletics".