John Upfold Pettit (September 11, 1820 – March 21, 1881) was an American lawyer and politician who served three terms as a U.S. Representative from Indiana from 1855 to 1861.

He studied law, was admitted to the bar in 1841 and commenced practice in Wabash, Indiana.

He served as chairman of the Committee on Expenditures in the Post Office Department (Thirty-fourth Congress).

Later, Pettit served as judge of the twenty-seventh judicial district of Indiana (1872–1880).

This article incorporates public domain material from the Biographical Directory of the United States Congress