The 1923 Illinois Fighting Illini football team represented the University of Illinois at Urbana-Champaign in the 1923 college football season. The Fighting Illini compiled an 8–0 record (5–0 against Western Conference opponents) and outscored their opponents by a combined total of 136 to 20. The team was selected retroactively as the national champion by the Boand System, College Football Researchers Association, Helms Athletic Foundation, and Parke H. Davis, and as a co-national champion by the Berryman QPRS system, National Championship Foundation, and Jeff Sagarin (using the ELO-Chess methodology).