List of state by-elections in Malaysia

This is a list of by-elections and scheduled by-elections for the Dewan Undangan Negeri (state legislative assembly) from its creation in 1954 until the present day.
Casual vacancies in the Dewan Undangan Negeri are filled by-elections, which may occur when a member of the Dewan Undangan Negeri dies, resigns or for some other reason. When a member of the Dewan Undangan Negeri resigns, he or she would normally tender the resignation to the Speaker. The Speaker has a discretion as to when to call a by-election and may not call one at all, for example, if 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.