The 1931 USC Trojans football team was an American football team that represented the University of Southern California (USC) in the Pacific Coast Conference (PCC) during the 1931 college football season. In their seventh season under head coach Howard Jones, the Trojans lost the opening game to Saint Mary's and then won the remaining ten games of the season. They finished the season with a 10–1 record (7–0 against PCC opponents), shut out six of eleven opponents, outscored all opponents by a total of 363 to 52, and won the PCC and national championships.