The 1945 Ashton-under-Lyne by-election was a by-election held on 2 October 1945 for the British House of Commons constituency of Ashton-under-Lyne.
The by-election was triggered by the elevation to the peerage of the town's Labour Party Member of Parliament (MP) William Jowitt, who was ennobled as Baron Jowitt.
The result was a victory for the Labour candidate Hervey Rhodes, who held the seat with 54% of the votes, and a swing in the Labour Party's direction.