The 1940 Spen Valley by-election was a by-election held for the British House of Commons constituency of Spen Valley on 1 June 1940.
The seat had become vacant when the Liberal National Member of Parliament Sir John Simon, had been elevated to the peerage as Viscount Simon.
[1] Simon had held the seat since the 1922 general election.
During the Second World War the political parties in the Coalition Government had agreed not to contest by-elections when a vacancy arose in any of the seats held by the other coalition parties.
As a result, the only candidate was William Woolley of the Liberal National Party, who was returned unopposed.