Robert Dickey "Jack" Sisco was an American football player, coach, and official. He served as head football coach at the University of North Texas from 1929 to 1941. With a record of 74–38–11, Sisco is the second winningest coach in school history, behind Odus Mitchell. His teams won seven conference championships and tied for three others.A native of Waco, Texas, Sisco prepped at Waco High School playing under coach Paul Tyson.