William Callahan

William Callahan may refer to:

• William A. Callahan, Canadian political scientist
• William F. Callahan (1891–1964), chairman of the Massachusetts Turnpike Authority
  • Callahan Tunnel or William F. Callahan Tunnel, a Boston Harbor tunnel
• William J. Callahan (Secret Service), Deputy Director of the United States Secret Service
• William J. Callahan, candidate in the 1936 United States Senate election in New Hampshire
• William P. Callahan (born 1950), American Roman Catholic bishop
• William R. Callahan (priest) (1931–2010), American Roman Catholic priest
• William R. Callahan (state representative) (1925–1976), Massachusetts state representative
• William Roger Callahan (1931–2022), journalist and politician in Newfoundland, Canada

Bill Callahan may refer to:

• Bill Callahan (American football) (born 1956), American football coach
• Bill Callahan (defensive back) (born 1964), American football player
• Bill Callahan (musician) (born 1966), American singer-songwriter
• Bill Callahan (TV producer), former producer and writer for Scrubs