Sir John Helias Finnie McEwen, 1st Baronet, also known as Jock McEwen, was a British Unionist politician who served in the House of Commons as Conservative Member of Parliament for Berwick and Haddington from the 1931 to 1945 general elections.

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.