The 1943 Buckingham by-election was a parliamentary by-election held in England on 4 April 1943 for the House of Commons constituency of Buckingham in Buckinghamshire. The by-election was held to fill the vacancy caused when the town's 45-year-old Conservative Party Member of Parliament Brigadier John Whiteley was killed in a plane crash in Gibraltar, along with another Conservative member, Victor Cazalet, and General Sikorski, the leader of the Polish government-in-exile. Whiteley had held the seat since a by-election in 1937.