Field Marshal Sir John Forster FitzGerald, GCB (c.1785 – 24 March 1877), was a soldier from Ireland who served as an officer in the British Army. He fought in the Peninsular War, seeing action at the Battle of Badajoz, the Battle of Salamanca and the Battle of Vitoria and commanding a brigade during the Battle of the Pyrenees before being captured by the French Army. He became Commandant of Quebec and then went on to be Commandant of Montreal, Quebec. He was given command of the 20th Regiment of Foot in Bombay before being given a divisional command in the Madras Army but shortly afterwards transferring to Bombay where he was given a divisional command of the Bombay Army. He later became a Liberal Member of Parliament.