Billy is a given name and a common nickname for William. Notable people with the name include:

• Billy the Kid (1859–1881), American Old West gunfighter born Henry McCarty, also known as William H. Bonney
• Billy Baldwin (decorator) (1903–1983), American interior decorator
• Billy Baldwin (baseball) (1951–2011), American Major League Baseball outfielder
• Billy Barnes (disambiguation)
• Billy Bevan (1887–1957), Australian actor
• Billy Bland (singer) (1932–2017), American R&B singer and songwriter
• Billy Boyd (disambiguation)
• Billy Blue (c. 1767 – 1834), African-American convict transported to Australia
• Billy Brewer (footballer) (died 1914), English professional footballer
• Billy Brown (disambiguation)
• Billy Burke (disambiguation)
• Billy Butler (singer) (1945–2015), American soul singer and songwriter
• Billy Cesare (born 1955), American football player
• Billy Connolly (born 1942), Scottish comedian
• Billy Corgan (born 1967), American musician, frontman of Smashing Pumpkins
• Billy Crawford (born 1982), Filipino-American actor and television personality
• Billy Crook (English footballer) (1926–2011)
• Billy Crook (American soccer) (born 1964)
• Billy Crystal (born 1948), American actor
• Billy Davis (disambiguation)
• Billy De Wolfe (1907–1974), American actor
• Billy Edwards Jr., American college football player
• Billy Eppler (born 1975), American baseball executive
• Billy Fox (politician) (1939–1974), Irish politician
• Billy Fox (boxer) (1926–1986), American light-heavyweight boxer
• Billy Forbes (Scottish footballer) (fl. 1911–1926)
• Billy Forbes (footballer, born 1990), Turks and Caicos Islands footballer
• Billy Gallagher (chef) (1948–2016), South African chef and businessman
• Billy Gibbons (born 1949), American musician
• Billy Gilmour (born 2001), Scottish footballer
• Billy Graham (1918–2018), American evangelist
• Billy Hahn (1953–2023), American basketball coach
• Billy Howard, English comedian
• Billy Howard (gridiron football) (1950–2005), American football player
• Billy Howerdel (born 1970), American musician, founding member of A Perfect Circle, frontman of ASHES dIVIDE
• Billy Herrington (1969–2018), American actor
• Billy Idol (born 1955), English rock musician
• Billy Joel (born 1949), American musician
• Billy Johnson (disambiguation)
• Billy Jones (disambiguation)
• ABilly S. Jones-Hennin (born 1942), American LGBT rights activist
• Billy Kametz (1987–2022), American voice actor
• Billy Knight (born 1952), American basketball player and executive
• Billy Knight (basketball, born 1979) (1979–2018), American basketball player
• Billy Knight (tennis) (born 1935), British tennis player
• Billy Magnussen (born 1985), American actor
• Billy Martin (1928–1989), American baseball player and manager
• Billy Masters (columnist) (born 1969), American gossip columnist
• Billy Masters (American football) (born 1944), former American Football League and National Football League player
• Billy Rush Masters (1950–1981), American composer and rock guitarist
• Billy Mays (1958–2009), American television salesperson
• Billy Mays (footballer) (1902–1959), Welsh footballer
• Billy McShepard (born 1987), American basketball player in the Israeli National League
• Billy Meier (born 1937), claims to be in regular contact with extraterrestrial beings
• Billy Mitchell (gamer) (born 1965), American gamer and restaurateur
• Billy Murray (disambiguation)
• Billy Name (1940–2016), American lighting designer
• Billy Ouattara (born 1992), Ghanaian/French basketball player
• Billy Parker (disambiguation)
• Billy Parks (1948–2009), American football player
• Billy Payne (born 1947), American golf administrator
• Billy Price (actor) (born 2000), English actor
• Billy Price (American football) (born 1995), American football player
• Billy Reid (fashion designer) (born 1964)
• Billy Rose (1899–1966), American impresario and husband of Fanny Brice
• Billy Joe Royal (1942–2015), American singer
• Billy Santoro (born 1975 or 1976), American gay pornographic film actor
• Billy Sharp (born 1986), English footballer
• Billy Sheehan (born 1953), American bass player
• Billy (slave), an African-American slave accused of treason
• Billy Smart Jr. (1934–2005), British circus performer and impresario
• Billy Snedden (1926–1987), Australian politician
• Billy Tauzin (born 1943), American lobbyist and politician
• Billy Taylor (disambiguation)
• Billy Unger (born 1995), American actor
• Billy Wade (cricketer) (1914–2003), South African cricketer
• Billy Wade (racing driver) (1930–1965), American race car driver
• Billy West (born 1952), American voice actor
• Billy Walker (disambiguation)
• Billy Williams (disambiguation)
• Billy Wright (disambiguation)
• Billy Zane (born 1966), American actor
• Reverend Billy, of Reverend Billy and the Church of Stop Shopping, New York City-based performance group

• Billy, a minor character from Thomas & Friends
• Billy, a character in Adventure Time
• Billy, the title character of Sport Billy, a TV cartoon show
• Billy Baker, a character in the television series All American
• Captain Marvel (DC Comics) Billy Batson, the superhero character in the Shazam series
• Billy Coen, a character in Resident Evil Zero
• Billy Cranston, the original Blue Ranger from the Power Rangers TV series
• Billy Dilley, the title character of the animated TV series Billy Dilley's Super-Duper Subterranean Summer
• the title character of Billy Elliot, a film about a boy aspiring to be a ballet dancer
• Billy Flynn, a lawyer from the play Chicago and its adaptations
• Billy Grant, a character in 1993 action/martial arts movie Showdown
• Billy Hargrove, a character on Stranger Things
• Billy Hitchcock, a character from the Final Destination
• Billy Loomis, a character from the 1996 film Scream
• Billy Jo Jive, an animated character in Sesame Street
• Billy K, a character in the Canadian TV series Catwalk
• Billy Kane, a Fatal Fury character
• Billy Kessler, a character in the comic book series G.I. Joe: A Real American Hero
• Billy Francis Kopecki, a character in the 1988 American fantasy comedy-drama movie Big
• Billy Lee Black, a character in Xenogears
• Billy Keikeya, aide to President Laura Roslin in the reimagined Battlestar Galactica TV series
• Billy Masterson, a character in the 1997 English-language French science fiction action movie The Fifth Element
• the title character of Billy Budd, a novella by Herman Melville
• Billy Nolan, a major antagonist in Stephen King's Carrie
• Billy Peltzer, a character in the 1984 and 1990 American comedy horror film Gremlins and Gremlins 2: The New Batch
• Billy Pilgrim, protagonist in Kurt Vonnegut's Slaughterhouse Five
• Billy Quinn, a character in the 1989 American-Canadian fantasy drama movie Prancer
• Billy Tate, a character in TV series Soap
• Billy Thunderman, from the tv series, The Thundermans
• Billy Twofeathers, a Native American character on Shining Time Station
• Billy Whizz, a character in the UK comic The Beano
• Billy Williams (Coronation Street), fictional character on the British soap opera Coronation Street
• Billy (Billy and Mandy), a character on The Grim Adventures of Billy and Mandy

• Billie (disambiguation)
• Billy (disambiguation)
• Bertrand de Billy (born 1965), French conductor
• Jacques de Billy (1602–1679), French Jesuit mathematician
• Jacques de Billy (abbot) (1535–1581), French patristic scholar, theologian, jurist, linguist and Benedictine abbot