William, Bill, or Billy Whelan may refer to:
William Whelan (surgeon) (1808–1865), Chief of the US Bureau of Medicine and Surgery W. J. Whelan (union leader) (1887–1960), Irish union leader Billy Whelan (Scottish footballer) (1906–1982), Scottish footballer William Joseph Whelan (1924–2021), American biochemist, Fellow of the Royal Society Billy Whelan (1935–1958), Irish footballer Bill Whelan (born 1950), Irish musician