Berwick and Haddington was a constituency of the House of Commons of the Parliament of the United Kingdom from 1918, when it replaced the separate Berwickshire and Haddingtonshire constituencies, until it was renamed Berwick and East Lothian for the 1950 general election. It elected one Member of Parliament (MP), using the first-past-the-post voting system.

Berwickshire was a county constituency of the House of Commons of the Parliament of the United Kingdom from 1708 to 1918, when it was amalgamated with neighbouring Haddington(shire) to form a new Berwick and Haddington constituency.