The United Kingdom parliamentary expenses scandal was a major political scandal that emerged in 2009, concerning expense claims made by members of the British Parliament in both the House of Commons and the House of Lords over the previous years. The disclosure of widespread misuse of allowances and expenses permitted to members of Parliament (MPs) aroused widespread anger among the UK public and resulted in a large number of resignations, sackings, de-selections and retirement announcements together with public apologies and the repayment of expenses. Several members, and former members, of both the House of Commons and the House of Lords were prosecuted and sentenced to terms of imprisonment.

The House of Commons is the lower house of the Parliament of the United Kingdom. Like the upper house, the House of Lords, it meets in the Palace of Westminster in London, England. The House of Commons is an elected body consisting of 650 members known as members of Parliament (MPs). MPs are elected to represent constituencies by the first-past-the-post system and hold their seats until Parliament is dissolved.