The 1940 Leeds North East by-election was a parliamentary by-election in England held on 13 March 1940 to elect a new Member of Parliament (MP) for the House of Commons constituency of Leeds North East.

The vacancy was caused by the resignation on 8 February 1940 of the sitting Member, Sir John Birchall, through the procedural device of appointment as Steward of the Chiltern Hundreds.^[1] He had held the seat since its creation for the 1918 general election.^[2]

The by-election was held during World War II, and the five largest political parties – Conservative, Labour, Liberal, National Labour and National Liberal – were all members of the Coalition Government. As such, they maintained an electoral pact and agreed not to contest any by-elections in seats held by any other party in the Government.

The Conservative candidate, John Craik-Henderson, was opposed only by Sydney Allen of the British Union of Fascists. Henderson won with 97.1% of the vote, but gained only 37.5% and lost his seat in the 1945 general election, when the seat was also contested by Labour and Liberal party candidates.^[3]