William "Willie" Carlin (born 6 October 1940 in Liverpool) is a former English footballer who played as a central midfielder.
Carlin began at Liverpool but moved to Halifax Town where he made his name as a midfield schemer before joining Carlisle United in 1964. He helped Carlisle win promotion to the Second Division before joining Sheffield United in 1967 and Derby County the following year. After another promotion, Carlin helped Derby establish themselves as a force in the First Division under Brian Clough. After spells playing for Leicester City and Notts County, he moved to Cardiff City in November 1973, being brought in by his former Leicester boss Frank O'Farrell. He made his debut during a 1-0 victory over Bolton Wanderers and was instrumental in helping the club avoid relegation before deciding to retire at the end of the season.