Casual vacancies in the Dewan Rakyat (House of Representatives) are filled through by-elections, which may occur when a member of the Dewan Rakyat dies, resigns or for some other reason. When a member of the Dewan Rakyat resigns, he or she would normally tender the resignation to the Speaker, who has a discretion as to whether and when to call a by-election. The Speaker may choose not to call one at all, if, for example, a general election is imminent.

Brackets around a date indicate that the candidate was unopposed when nominations closed. These candidates were declared "elected unopposed" with effect from the date of the closing of nominations, and there was no need to hold a by-election.