Rex is a male given name, short for Rexford or Reginald, derived from the Latin word rex, meaning "king". This is the etymological root word for king in several languages.

• Rex (artist) (birth name not made public; c.1943–2024), American gay erotic artist
• Rex Addison, Australian architect
• Rex Andrew Alarcon (born 1970), Filipino prelate of the Roman Catholic church
• Rex Alexander (1924–1982), American basketball and tennis coach
• Rex Allen (1920–1999), American actor and singer
• Rex Allen, Jr. (born 1947), American singer and son of the above
• Rex Applegate (1914–1998), American military officer
• Rex Armistead (1930–2013), American private detective
• Rex Babin (1962–2012), American political cartoonist
• Rex Baddeley (born 1941), New Zealand cricketer
• Rex Ballard, American cinematographer
• Rex T. Barber (1917–2001), American fighter pilot
• Rex Barnes (born 1959), Canadian politician
• Rex Barnett (born 1938), American politician, and former officer of the Missouri State Highway Patrol
• Rex Barney (1924–1997), American baseball pitcher and announcer
• Rex Barrat (1914–1974), French artist
• Rex Battarbee (1893–1973), Australian artist
• Rex Baxter (born 1936), American golfer
• Rex Beach (1877–1949), American novelist and playwright
• Rex Bell (1903–1962), American actor and politician
• Rex M. Best, American soap opera writer
• Rex Black (born 1964), American author, software engineer and entrepreneur
• Rex Brandt (1914–2000), American artist and educator
• Rex Brasher (1869–1960), American painter
• Rex Briggs (born 1971), American author, analyst and researcher
• Rex Brothers (born 1987), American baseball player
• Rex Brown (born 1964), bassist of heavy metal band Pantera
• Rex Burkhead (born 1990), American football player
• Rex Caldwell (born 1950), American golfer
• Rex Carroll, American guitarist
• Rex L. Carter (1925–2014), American lawyer and politician
• Rex Cauble (1913–2003), American banker, businessman, rancher and real estate agent
• Rex Cecil (1916–1966), American baseball player
• Rex Chapman (born 1967), American basketball player
• Rex Chikoko, Malawian investigative journalist and media analyst
• Rex Clark (1935–1978), Australian army officer
• Rex Cherryman (1897–1928), American stage and screen actor
• Rex Vicat Cole (1870–1940), English painter
• Rex Collinge (born 1935), English first-class cricketer and Royal Air Force officer
• Rex Connor (1907–1977), Australian politician
• Rex Cramphorn (1941–1991), Australian theatre director, costume designer, theatre critic, theorist and translator
• Rex Crawford (1932–2022), Canadian farmer and politician
• Rex M. Cunningham (1907–1969), American politician and World War II veteran
• Rex Davis (1890–1951), English soldier, silent film actor and sportsman
• Rex D. Davis (1924–2008), American federal law enforcement officer
• Rex Dallas (born 1938), Australian country musician, singer, songwriter, yodeler and bush balladeer
• Rex Damschroder (born 1950), American politician
• Rex De Garis (1896–1967), Australian footballer
• Rex de Silva (1918–2005), Ceylonese aviator
• Rex Dockery (1942–1983), American football player and coach
• Rex Downing (1925–2020), American child actor
• Rex Eisen né Tod Rex Salvador, ex-guitarist of Murderdolls, Static-X and Dope
• Rex Ellsworth (1907–1997), American Thoroughbred racehorse breeder
• Rex Enright (1901–1960), American football and basketball player, coach and college athletics administrator
• Rex Everhart (1920–2000), American actor
• Rex Fell (1944/1945–2016), New Zealand thoroughbred horse breeder
• Rex Forehand (born 1945), American psychologist
• Rex Forrester (1928–2001), New Zealand hunting and fishing specialist
• Rex Frederick (born 1936), American basketball coach and player
• Rex Garrod (1943–2019), English inventor and roboteer
• Rex Garvin (1940–2013), American instrumentalist and singer-songwriter
• Rex Gatchalian (born 1979), Filipino politician
• Rex Geard (1927–1982), Australian footballer
• Rex Geveden (born 1962), American businessman, CEO of BWX Technologies
• Rex Gibson (1932–2005), English academic writer
• Rex Gildo (1939–1999), German singer
• Rex Goh (born 1951), Singaporean-Australian guitarist
• Rex Goreleigh (1902–1986), American painter, educator
• Rex Goudie (born 1985), Canadian singer and 2005 Canadian Idol runner-up
• Rex Griffin (1912–1959), American singer-songwriter
• Rex Grossman (born 1980), American football player
• Rex Grossman Sr. (1924–1980), American football player
• Rex Hadnot (born 1982), American football player
• Rex Harrison (1908–1990), British actor
• Rex Hartwig (1929–2022), Australian tennis player
• Rex Harvey (1946–2019), American decathlete and engineer
• Rex Hazlewood (disambiguation), several people
• Rex Hillier (born 1956), Canadian politician
• Rex Hobcroft (1925–2013), Australian pianist and music administrator
• Rex Hudler (born 1960), American baseball player
• Rex Hughes, American basketball coach
• Rex Humbard (1919–2007), American television evangelist
• Rex Hunt (born 1949), Australian television and radio personality and former football player
• Rex Hunt (diplomat) (1926–2012), British diplomat, Governor of the Falkland Islands from 1980 to 1985
• Rex Ingamells (1913–1955), Australian poet
• Rex Ingram (disambiguation), several people
• Rex Jackson (1928–2011), Australian politician
• Rex Jameson (1924–1983), English comedian and drag queen
• Rex Lee Jim (born 1962), Native American politician
• Rex Job (1910–1999), Australian footballer
• Rex Johns (1935–2009), Australian footballer
• Rex Johnston (1937–2019), American baseball player
• Rex Jung, American psychologist
• Rex Kalamian, American basketball coach
• Rex Keeling (1943–2010), American football player
• Rex Kern (born 1949), American football player
• Rex Kieffer Jr. (1929–2001), American politician
• Rex Kilpatrick (1881–1955), American football player and investment banker
• Rex King-Clark (1913–2007), English soldier, pilot, racer, photographer, author, and diarist
• Rex Kirton, New Zealand politician
• Rex Kodippili (1938–2023), Sri Lankan film actor and producer
• Rex Lassalle (born 1945), Trinidadian alternative medicine practitioner and former lieutenant
• Rex Lawson (1938–1971), Nigerian singer, trumpeter and bandleader
• Rex Layne (1928–2000), American heavyweight boxer
• Rex Lease (1903–1966), American actor
• Rex Lee (disambiguation), several people
• Rex Lewis-Clack (born 1995), American pianist and musical prodigy
• Rex Liddy (born 1992), Australian football player
• Rex Linn (born 1956), American actor
• Rex Makin (1925–2017), English solicitor and philanthropist from Liverpool
• Rex Marshall (1919–1983), American actor, television announcer and radio personality
• Rex Distin Martienssen (1905–1942), South African architect
• Rex Mason (1885–1975), New Zealand politician
• Rex Maughan (1936–2021), the founder, president and CEO of Forever Living Products and Terry Labs
• Rex McCandless (1915–1992), Northern Irish motorcycle racer
• Rex McDougall (1878–1933), English stage and film actor
• Rex McGill (born 1949), New Zealand cricketer
• Rex Morgan (disambiguation), several people
• Rex Mossop (1928–2011), Australian rugby player
• Rex Murphy (1947–2024), Canadian commentator
• Rex Nan Kivell (1898–1977), New Zealand-born British art collector
• Rex Navarrete (born 1969), Filipino American comedian
• Rex Neame (1936–2008), English cricketer and brewer
• Rex Nelon (1932–2000), American southern gospel musician
• Rex Nelson, American college sports broadcaster, columnist, reporter, author, political appointee and chronicler of Arkansas history
• Rex Nettleford (1933–2010), Jamaican scholar
• Rex Newmark (born 1984), British television personality
• Rex Norris (disambiguation), several people
• Rex Nutting, American journalist, economist and columnist
• Rex Ogle, American author
• Rex O'Malley (1901–1976), English actor
• Rex Omar, Ghanaian musician
• Rex Orr (1923–2011), New Zealand rugby player
• Rex Paterson (1902–1978), British agriculturalist
• Rex Patrick (born 1967), Australian politician
• Rex Patterson (1927–2016), Australian politician
• Rex Paul (born 1945), real name of Guyanese-born American radio journalist Kojo Nnamdi
• Rex Pemberton (born 1983), Australian extreme sport athlete and motivational speaker
• Rex R. Perschbacher (1946–2018), American law professor
• Rex Piano, American film director, screenwriter, TV actor and producer
• Rex Pickett, American novelist and filmmaker
• Rex Pierson (1891–1948), English aircraft designer
• Rex Pilbeam (1907–1999), Australian politician
• Rex Rabanye (1944–2010), South African jazz fusion and soulful pop musician
• Rex Rammell (born 1961), American politician and veterinarian
• Rex Ray (1956–2015), American graphic designer
• Rex Reason (1928–2015), American actor
• Rex Reed (born 1938), American journalist and film critic
• Rex Richardson (born 1983), American politician
• Rex Rienits (1909–1971), Australian writer
• Rex M. Rogers (born 1952), American author, broadcaster and televangelist
• Rex Rudicel (1912–2000), American basketball player
• Rex Ryan (born 1962), American football coach
• Rex Salas (born 1962), American record producer, songwriter, musical director and music arranger
• Rex Sanders (1922–2017), English military aviator
• Rex Shelley (1930–2009), Singaporean author
• Rex Sinquefield (born 1944), American businessman, investor and philanthropist
• Rex Slinkard (1887–1918), American painter and teacher
• Rex Smith (disambiguation), several people
• Rex Wakely Smith (1930–2013), South African rally driver and philatelist
• Rex Solomon (born 1966), American jewelry store owner and former capella directory publisher
• Rex Stewart (1907–1967), American jazz cornetist
• Rex Stout (1886–1975), American author
• Rex Taylor (1889–1968), American screenwriter
• Rex Terp (born 1970), Australian rugby player
• Rex Terry (1888–1964), American banker and politician
• Rex Tillerson (born 1952), 69th United States Secretary of State
• Rex Tilley (1929–2016), English footballer
• Rex Townley (1904–1982), Australian politician
• Rex Trailer (1928–2013), American television personality, broadcast pioneer, cowboy and Country and Western recording artist
• Rex Tremlett (1903–1986), British-South African mining engineer and journalist
• Rex Tso (born 1987), Hong Kong super-flyweight boxer
• Rex Tucker (1913–1996), British television director in the 1950s and 1960s
• Rex Tucker (American football) (born 1976), American football player
• Rex Varghese, Indian bodybuilder
• Rex Vijayan (born 1983), Indian composer, guitarist, singer, record producer and multi-instrumentalist
• Rex A. Wade (born 1936), American historian and author
• Rex Wailes (1901–1986), English engineer and historian on aspects of engineering history
• Rex Walheim (born 1962), American astronaut
• Rex E. Wallace (born 1952), American linguist and classical scholar
• Rex Walters (born 1970), American basketball player and coach
• Rex Warner (1905–1986), English classicist, writer and translator
• Rex Weyler (born 1947), American-Canadian author, journalist and ecologist
• Rex Whistler (1905–1944), English painter, designer and illustrator
• Rex White (born 1929), American race car driver
• Rex Marion Whitton (1898–1981), American federal highway administrator
• Rex Williams (disambiguation), several people
• Rex Willis (1924–2000), Welsh rugby player
• Rex Wilson (disambiguation), several people
• Rex Winsbury (1935–2015), English journalist and author
• Rex Yeatman (1919–1995), English cricketer
• Rex Yetman (1933–2009), Canadian musician
• Rex Ziak, American writer, historian, tour guide and documentarian

• Rex, from Toy Story
• Rex Dangervest, from The Lego Movie 2: The Second Part
• Rex, the titular character from the British claymation show Rex the Runt
• Rex, the villain from the Canadian animated show Wild Kratts