Martin Calvin Hobart (August 1, 1835 – March 20, 1919) was an American farmer and Republican politician.

During the American Civil War he served as an officer in the Iron Brigade of the Army of the Potomac.

He served one term in the Wisconsin State Assembly, representing Columbia County.

He was wounded in the intense fighting at Gainesville, Virginia, during the first day of the Second Battle of Bull Run.

While in prison, Hobart was promoted to major and then lieutenant colonel, but was never mustered at that rank.