Callaghan most commonly refers to O'Callaghan, an Anglicized Irish surname.

Callaghan may also refer to:

People
 Aaron Callaghan (born 1966), Irish footballer with Crewe Alexandra and Crusaders
 Sir Alfred John Callaghan (1865–1940), Irish politician and barrister 
 Alice Callaghan (born 1947), Canadian Catholic nun and Episcopalian priest
 Aloysius R. Callaghan (born 1946), American Roman Catholic priest
Amanda Callaghan ( from 1989), British entomologist
Amy Callaghan (born 1992), British Member of Parliament for Scottish National Party, elected 2019
Andrew Callaghan (born 1997), American journalist
 Audrey Callaghan (1915–2005), English dietician; wife of James, mother of Margaret
 Ayden Callaghan (born 1981), English actor
 Barry Callaghan (born 1937), Canadian author; son of Morley
 Barry Callaghan (footballer) (born 1986), Scottish footballer with Queen of the South
 Sir Bede Callaghan (1912–1993), Australian banker and university administrator 
 Sir Bill Callaghan (born 1948), British trade unionist
 B. J. Callaghan (born 1981) American soccer coach 
 Brendan Callaghan (born 1948), British psychologist of religion
 Bryan Callaghan Jr. (1852–1912), mayor of San Antonio, Texas 
Catherine Callaghan (1931–2019), American linguist
 Cecil Callaghan (1890–1967), Australian Army officer 
 Cindy Callaghan (born c. 1976), American author of children's books
 Colleen Callaghan (1931–2020), American hair stylist 
 Craig Callaghan (born 1976), Australian Rules footballer with Fremantle and St Kilda
 Daniel Callaghan (disambiguation), several people 
 David Callaghan (disambiguation), several people
 Duke Callaghan (1914–2002), American cinematographer
 Eamonn Callaghan, Irish Gaelic footballer 
 Elizabeth Callaghan (1802–1852), Irish convict, early settler of Australia (wife of John Batman)
 Emma Callaghan (1884–1979), Australian Aboriginal midwife and activist
Ernie Callaghan (1910–1972), English footballer with Aston Villa 
 Finlay Callaghan (born 2001), Scottish rugby union player with Glasgow Warriors 
 Finn Callaghan (born 2003), Australian Rules footballer with Greater Western Sydney Giants
 Frank Callaghan (1891–1980), New Zealand agricultural instructor and scientific administrator
 Fred Callaghan (1944–2022), English footballer with Fulham, manager with Brentford 
Sir George Callaghan (1852–1920), British officer in the Royal Navy
 Georgina Callaghan ( from 2005), English singer and songwriter, performs under the name Callaghan
 Guy Callaghan (born 1970), butterfly swimmer from New Zealand 
 Helen Callaghan (1923–1992), Canadian baseball infielder; sister of Marge 
 Hugh Callaghan (1930–2023), Irishman wrongly convicted of terrorist murder, one of the Birmingham Six 
 Ian Callaghan (born 1942), English footballer with Liverpool, Swansea City and England 
 James Callaghan (1912–2005), British politician who served as Prime Minister of the United Kingdom; husband of Audrey, father of Margaret
 James Callaghan (disambiguation), several others 
 Jeremy Callaghan (born 1967), Australian actor 
John Callaghan (disambiguation), several people 
 Joseph Cruess Callaghan (1893–1918), Irish First World War flying ace
 Kathy Callaghan (born 1962), American handball goalkeeper 
 Kristian Callaghan (born 1993), English sport shooter 
 Leo Callaghan (1924–1987), Welsh football referee
 Leonie Callaghan (born 1959), Australian cricketer
 Marge Callaghan (1921–2019), Canadian baseball in fielder; sister of Helen 
Marissa Callaghan (born 1985), footballer from Northern Ireland with Cliftonville
 Martin Callaghan (born 1962), Australian water polo player
 Martina Callaghan, Irish medical physicist 
 Marty Callaghan (1900–1975), American baseball outfielder
 Mary Callaghan ( from 2019), Irish Social Democrats politician
 Mary Rose Callaghan (born 1944), Irish novelist 
 Mike Callaghan (born 1963), American politician and attorney 
 Morley Callaghan (1903–1990), Canadian novelist; father of Barry 
 Margaret Jay, Baroness Jay of Paddington (née Callaghan; born 1939), British politician for the Labour Party; daughter of James and Audrey
 Nev Callaghan (1936–2016), Australian rugby league player
 Noel Callaghan (born 1955), Australian tennis player and coach 
 Nigel Callaghan (born 1962), English footballer with Watford and Derby County 
 Pat Callaghan (politician) (1927–2009), Canadian politician
Patrick Callaghan (1879–1959), Scottish footballer with Hibernian and Scotland
 Patrick Desmond Callaghan (1926–1992), officer in the Pakistan Air Force
 Paul Callaghan (1947–2012), New Zealand physicist 
 Paul Callaghan (Gaelic footballer) (born 1971), Irish Gaelic footballer and coach 
 Pól Callaghan ( from 2010), Irish politician
 Richard Callaghan ( 1960s–1999), American figure skater and coach
Sheila Callaghan (born 1973), American playwright
 Simon Callaghan (born 1983), English racehorse trainer
 Slade Callaghan (born 1970), Barbadian jockey
 Stan Callaghan (1916–1989), Australian rugby league footballer
 Stephanie Callaghan (born 1971), Scottish politician for Scottish National Party, Member of the Scottish Parliament elected 2021
 Steve Callaghan ( from 1999), American screenwriter and voice actor 
 Stuart Callaghan (born 1976), Scottish footballer with Hamilton, Brechin and Berwick 
 Tabby Callaghan (born 1981), Irish musician
Terry Callaghan (born 1945), British Arctic ecologist
 Jeremiah Thomas Fitzgerald Callaghan (1827–1881), Irish colonial administrator (governor of the Falkland Islands, the Bahamas and The Gambia) 
 Thomas Callaghan (disambiguation), several people
William Callaghan (disambiguation), several people

Fictional characters
 Clarissa Callaghan, from the video game Valkyria Chronicles III
 Robert Callaghan, the main antagonist from the movie Big Hero 6
 Sam Callaghan, protagonist of Australian / Singaporean television series Serangoon Road 
 Slim Callaghan, private detective in novels by Peter Cheyney

Places
 Callaghan, New South Wales, Australia
 Callaghan, Edmonton, Canada
 Callaghan, Virginia, United States
 Callaghan, Texas, United States 
 Callaghan Lake Provincial Park, British Columbia, Canada
 Callaghan Park, horseracing venue in Rockhampton, Queensland, Australia
 Callaghan Square, Cardiff, Wales
 Callaghan Valley, British Columbia, Canada
 Mount Callaghan, British Columbia, Canada

Ships
 , American military support vessel 
 , United States Navy destroyer
 , United States Navy destroyer

Other
 Callaghan Apartments, Wyoming, United States 
 Merritt E. Callaghan Intermediate School, St Louis, United States

See also
 
 Callahan (disambiguation)
 Callihan, a surname