 During World War II , Singapore was conquered and occupied by the Japanese Empire from 1942 to 1945 . When the war ended , Singapore reverted to British control , with increasing levels of self @-@ government being granted , culminating in Singapore 's merger with the Federation of Malaya to form Malaysia in 1963 . But social unrest and disputes between Singapore 's ruling People 's Action Party and Malaysia 's Alliance Party resulted in Singapore 's separation from Malaysia . Singapore became an independent republic on August 9 , 1965 . 
