USS O. M. Pettit (1857) was a steamer acquired by the Union Navy during the American Civil War. She was used by the Navy as a tugboat to service Union Navy ships blockading ports of the Confederate States of America. Oliver M. Pettit, a wooden side wheel steamer built in 1857 at Williamsburg, New York, was purchased by the Navy at New York City 17 August 1861, and commissioned at New York Navy Yard 4 October 1861, as O. M. Pettit, Acting Master A. S. Gardner in command.