William Calhoun (1934–1989) was a wrestler who used the name "Haystack" or "Haystacks" Calhoun.

William Calhoun or Bill Calhoun may also refer to:

• WC (rapper) (William L. Calhoun, Jr., born 1970), West Coast rapper
• William Lowndes Calhoun (1837–1908), American attorney and politician from the state of Georgia who served as Mayor of Atlanta
• William B. Calhoun (1796–1865), U.S. Representative from Massachusetts
• Bill Calhoun (basketball) (born 1927), American former professional basketball player
• Bill Calhoun (baseball) (1890–1955), American professional baseball player
• William L. Calhoun (admiral) (1884–1963), U.S. Navy
• William J. Calhoun (1848–1916), American attorney, government official, and friend of President William McKinley
• Will Calhoun (born 1964), American drummer
• Bill Calhoun, a secondary lead character in the Broadway musical Kiss Me, Kate

• Members of the South Australian Legislative Council, 1871–1875
• Members of the South Australian Legislative Council, 1873–1877
• Members of the South Australian Legislative Council, 1875–1878
• Members of the South Australian Legislative Council, 1877–1881
• Members of the South Australian Legislative Council, 1878–1881
• Members of the South Australian Legislative Council, 1881–1884
• Members of the South Australian Legislative Council, 1881–1885
• Members of the South Australian Legislative Council, 1884–1887
• Members of the South Australian Legislative Council, 1885–1888
• Members of the South Australian Legislative Council, 1887–1890
• Members of the South Australian Legislative Council, 1888–1891
• Members of the South Australian Legislative Council, 1890–1893
• Members of the South Australian Legislative Council, 1891–1894
• Members of the South Australian Legislative Council, 1893–1896
• Members of the South Australian Legislative Council, 1894–1897
• Members of the South Australian Legislative Council, 1896–1899
• Members of the South Australian Legislative Council, 1897–1900
• Members of the South Australian Legislative Council, 1899–1902
• Members of the South Australian Legislative Council, 1900–1902
• Members of the South Australian Legislative Council, 1902–1905
• Members of the South Australian Legislative Council, 1905–1906
• Members of the South Australian Legislative Council, 1905–1908
• Members of the South Australian Legislative Council, 1906–1910
• Members of the South Australian Legislative Council, 1908–1910
• Members of the South Australian Legislative Council, 1910–1912