Raised in Devonshire 1688 as Sir Richard Peyton's Regiment of Foot, the regiment was numbered as the 20th in 1751. In 1782 it was titled as the 20th (East Devonshire) Regiment of Foot. Bizarrely - and in common with many other units at the time, this Devonshire regiment found itself becoming the Lancashire Fusiliers in the Cardwell Reforms of 1881 and the county regiment of central Lancashire. Militia and Volunteer Force battalions were also incorporated in to the regimental establishment at this time.
The regiment was amalgamated in 1968 with the Royal Northumberland Fusiliers, the Royal Warwickshire Fusiliers and the Royal Fusiliers (City of London Regiment) to form the Royal Regiment of Fusiliers.