The 2013 Aberdeen Donside by-election is a by-election that was held for the Scottish Parliament constituency of Aberdeen Donside on Thursday 20 June, following the death from cancer of the constituency's MSP, Brian Adam. SNP list MSP for the North-East region, Mark McDonald, resigned his seat to contest the constituency by-election. McDonald held the seat for the SNP, but with a significantly reduced majority on a lower turnout.