William S. Stewart (11 February 1872 – July 1945) was a Scottish footballer who was born in Coupar Angus.
He played as an inside forward before switching to his favoured half back position.
At Newton Heath, which was renamed Manchester United in 1902, he scored a goal in the club's first Football Alliance match against Sunderland Albion on 21 September 1889.
After scoring 23 goals in 149 appearances for the Heathens, he left the club in May 1895 for Luton Town.
This biographical article related to association football in Scotland, about a defender born in the 1870s, is a stub.