The 66th (Berkshire) Regiment of Foot was an infantry regiment of the British Army, raised in 1756. Under the Childers Reforms it amalgamated with the 49th (Hertfordshire) Regiment of Foot to form the Princess Charlotte of Wales's in 1881.
The Battle of Albuera in May 1811, where the 2nd battalion of the 66th Regiment suffered heavy losses: 16 of its officers and 310 of its men killed, wounded or missing