Merlyn is an alternate spelling of Merlin, a wizard in the Arthurian legend.
Merlyn may also refer to:
- Merlyn (cricket), an automated bowling machine used by the England cricket team
- Merlyn (DC Comics), a DC Comics supervillain and arch-rival of Green Arrow
- Merlyn (Marvel Comics), a supporting character of Marvel Comics' Captain Britain
- Merlyn (racing car), racing cars built by Colchester Racing Development (CRD)
- The Book of Merlyn, the posthumously published final book in T. H. White's The Once and Future King
- Merlyn Mantle (1932–2009), American writer and wife of baseball player Mickey Mantle
- Merlyn Rees (1920–2006), British politician
- Randal Schwartz (born 1961), or merlyn, American technology writer, system administrator and programming consultant
- Merlyn Orville Valan (1926-2010), American farmer and politician
- Merlyn Wood (born 1996), member of Brockhampton