William D. Carnihan (12 July 1894 – 16 November 1964) was a Scottish-born footballer who earned two caps with the U.S. national team.
He began his professional career in Scotland before moving to the American Soccer League.
Carnihan began his career with Scottish club Blantyre Victoria.
In 1922, he moved to the United States where he signed with Bethlehem Steel of the American Soccer League.
Over the next eight seasons, he was a regular in the Bethlehem midfield, playing 210 games in the ASL.