2021 Chesham and Amersham by-election

A by-election was held in the United Kingdom Parliament constituency of Chesham and Amersham on 17 June 2021. This is because the previous Member of Parliament, Dame Cheryl Gillan, had died on 4 April 2021. Gillan had served as MP for the constituency since 1992. The by-election was the third to the 58th Parliament, which was elected in 2019.
The Liberal Democrat candidate, Sarah Green, won the by-election with 56.7% of the vote and a swing from the Conservatives of 25.2%. This is the first time a non-Conservative candidate has won this seat since it was formed in 1974.