The Bury by-election, 1902 was a by-election held in England on 10 May 1902 for the House of Commons constituency of Bury in Lancashire. It was the first by-election gain by the Liberal Party from the ruling Conservatives in the Parliament of 1900–1906 and it can arguably be said to have set in motion the swing to the Liberals from the Tories which brought twenty by-election gains in all over the following months, leading to the Liberals landslide victory in the 1906 general election.