66th (Berkshire) Regiment of Foot was an infantry regiment of the British Army, formed in 1758 and amalgamated into The Princess Charlotte of Wales's (Berkshire Regiment) in 1881. The regiment was raised by the redesignation of the 2nd Battalion, 19th Regiment of Foot in April 1758, ranked as the 66th Regiment of Foot. In 1782 they took a county title as the 66th (Berkshire) Regiment of Foot.