Fitz John Porter (August 31, 1822 – May 21, 1901) (sometimes written FitzJohn Porter or Fitz-John Porter) is a career United States Army officer and a Union General during the American Civil War.

He is most known for his performance at the Second Battle of Bull Run and his subsequent court martial.

Although Porter serves well in the early battles of the Civil War, his military career is ruined by the controversial trial, which is called by his political rivals.

After the war, he works for almost 25 years to restore his tarnished reputation and is finally restored to the army's roll.