The Poplar by-election was a Parliamentary by-election. It returned one Member of Parliament to the House of Commons of the United Kingdom, elected by the first past the post voting system.
In February 1914, Sydney Buxton, the Liberal MP for Poplar since 1886, resigned to take up an appointment as Governor-General of the Union of South Africa.
The Unionist campaign was given a boost by the Conservative by-election victory in nearby Bethnal Green South West declared the day before polling day.
A General Election was due to take place by the end of 1915. By the autumn of 1914, the following candidates had been adopted to contest that election. Due to the outbreak of war, the election never took place.