The 1945 Neath by-election, was a parliamentary by-election held for the British House of Commons constituency of Neath in South Wales. Neath was considered a safe seat for the Labour Party and had been held by William Jenkins since the 1922 general election. No other candidate had stood in the seat at the last general election. Jenkins died on 8 December 1944, but as World War II was still underway, the process of calling a by-election was slow, and the date was ultimately set as 15 May 1945.