The 1978 Glasgow Garscadden by-election was a parliamentary by-election held on 13 April 1978 for the British House of Commons constituency of Glasgow Garscadden, in the north west periphery of the City of Glasgow.
It was won by Donald Dewar of the Labour Party. It was important in that it was widely seen as halting the Scottish National Party (SNP) tide in the 1970s.