William McCoy (disambiguation) refers to multiple individuals who share the same name but have different backgrounds and contributions. One notable William McCoy was a famous American bootlegger during the Prohibition era, known for his high-quality liquor and the phrase "The Real McCoy," which signifies authenticity. Other individuals named William McCoy include a 19th-century American politician and a contemporary artist. Each of these figures has made distinct impacts in their respective fields, highlighting the diverse legacies associated with the name.