The 1973 Dundee East by-election, in Scotland, was held on 1 March 1973. It was one of three UK parliamentary by-elections held on that day. It was caused by the appointment of George Thomson as a European commissioner. George Machin retained the seat for Labour, but only narrowly. There was a strong showing by the Scottish National Party, which prefigured their serious breakthrough at the Govan by-election later in the year, and the two general elections of 1974.