Gatton was a parliamentary borough in Surrey, one of the most notorious of all the rotten boroughs. It elected two Members of Parliament (MPs) to the House of Commons from 1450 until 1832, when the constituency was abolished by the Great Reform Act. Around the time of that Act it was often held up by reformers as the epitome of what was wrong with the unreformed system.

A rotten or pocket borough, also known as a nomination borough or proprietorial borough, was a parliamentary borough or constituency in England, Great Britain, or the United Kingdom before the Reform Act 1832, which had a very small electorate and could be used by a patron to gain unrepresentative influence within the unreformed House of Commons. The same terms were used for similar boroughs represented in the 18th-century Parliament of Ireland. The Reform Act 1832 abolished the majority of these rotten and pocket boroughs.