John Scott Maclay, 1st Viscount Muirshiel, was a British politician, sitting as a National Liberal and Conservative Member of Parliament before the party was fully assimilated into the Unionist Party in Scotland in the mid-1960s.

The National Liberal Party, known until 1948 as the Liberal National Party, was a liberal political party in the United Kingdom from 1931 to 1968. It broke away from the Liberal Party on the issue of abandoning Free trade and supporting protectionism, and later co-operated and merged with the Conservative Party.