Irvin St. Clair Pepper (June 10, 1876 – December 22, 1913) was a Democratic U.S. Representative from Iowa's 2nd congressional district. Pepper was born on a farm in Davis County, Iowa. He attended public schools and graduated from Southern Iowa Normal School at Bloomfield in 1897. He later served as principal of the Atalissa, Iowa High School and of the Washington School at Muscatine, Iowa. Pepper had planned to enter the contest in Iowa for the U.S. Senate seat held by Albert B. Cummins, in what would be Iowa's first direct election of a U.S. Senator.