By Agence France-Presse,
Sultan Muhammad V's decision marks the first time a king has abdicated in the Muslim-majority country since it gained independence from Britain in 1957.
"The National Palace informs that his majesty has resigned as the 15th king effective January 6," said a statement from the palace.
It did not give any reason for the 49-year-old royal's move.
But there had been a question mark over the reign of the king, who ascended to the throne in December 2016, since he took a leave of absence for medical treatment in November.
Reports then circulated online that he had married a former Miss Moscow in Russia -- although royal officials in Malaysia have so far not commented on the rumours.
Speculation intensified about his future this week when the country's Islamic royals reportedly held a special meeting.
Malaysia is a constitutional monarchy, with an unique arrangement where the throne changes hands every five years between rulers of the nine Malaysian states headed by centuries-old Islamic royalty.