Thomas David Patrick O'Malley Sr. (March 24, 1903 – December 19, 1979) was an American Democratic politician from Milwaukee, Wisconsin.

He first sought elected office in 1928, running for United States House of Representatives in Wisconsin's 5th congressional district.

[3] O'Malley faced a bitter primary race running for re-election in 1934, but managed to prevail against four Democratic challengers.

[5][6] O'Malley's most noteworthy contribution during his six years in Congress was likely the Johnson–O'Malley Act, to subsidize education, medical facilities, and other services for the Native American population.

[7] After leaving Congress, he was appointed regional director for the Wages and Hours division of the United States Department of Labor.