Although it is possible to trace the existence of a third infantry brigade in the Peninsula war and at Waterloo, it was not until the official formation in 1857 that 3 Infantry Brigade gained its name. Following its official formation in Aldershot there were only two occasions, prior to the Army reorganisation of 1904, when a third infantry brigade was required for operational reasons. The first was during the Egyptian Campaign of 1882 and the second was the initial stages of the Boer War. The reforms of Haldane after the Boer War consolidated the 3rd Infantry Brigade as a permanent regular formation. 3 Infantry Brigade served on the Western Front throughout the First World War and in North Africa and Italy as part of the First Division during the Second Ward War. After 1945 the Brigade served in Palestine, Cyprus and Egypt until it was disbanded in 1962.
The Brigade has been reformed on two occasions since 1962. On both occasions 3 Infantry Brigade was formed to fulfil an operational role in Northern Ireland. From 1971 to 1981 and then 1988 until 2004 the brigade was responsible for the south of Northern Ireland including the South Armagh area, notoriously known as bandit country.