 A battalion was formed on 1 January 1938 and eventually a second battalion on 1 December 1941.The 1st Bn Malay Regiment was famous for its successful defence of Opium Hill (), Singapore, in the Battle of Pasir Panjang during the Battle of Singapore.The Battle of Opium Hill on 14 February 1942 involved 42 soldiers commanded by Lt. Adnan Bin Saidi who defended their position against attack from the 18th Division of the Japanese Imperial Army under Lt. Gen. Renya Mutaguchi.