The 1911 Brentford by-election was a Parliamentary by-election held on 23 March 1911. It returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom, elected by the first past the post voting system.
The incumbent Conservative Member of Parliament, Lord Alwyne Compton, resigned for private and business reasons.
The seat was held unopposed for the Conservative Party by William Joynson-Hicks.