Malaysia Day is held on September 16 every year to commemorate the establishment of the Malaysian federation on the same date in 1963. It marked the joining together of Malaya, North Borneo, Sarawak, and Singapore to form Malaysia.
The formation of the new federation was planned to occur on June 1, 1963, but was later postponed to August 31, 1963, in order to coincide with the sixth Hari Merdeka. Several issues related to the Indonesian and the Filipino objection to the formation of Malaysia delayed the declaration to September 16 of the same year.
The postponement was also done to allow the United Nations team time to conduct referendums in North Borneo (now Sabah) and Sarawak regarding the two states participation in a new federation.
The formation of Malaysia was made possible through the introduction of the Malaysia Bill to the Malayan Parliament on July 9, 1963, and consent from the Yang di-Pertuan Agong on August 29, 1963.
Prior to the formation of Malaysia, Singapore and North Borneo unilaterally declared independence from the United Kingdom on August 31, 1963, thus coinciding with the sixth anniversary of the Malayan independence.
Malaysia Day is not a public holiday. However, it is coincidental with the birthday of the Yang di-Pertua of Sabah, making the day a public holiday in Sabah.