Leo is a given name in several languages. In European languages, it is usually a masculine given name and it comes from the Latin word leo, which in turns comes from the Greek word λέων meaning "lion". It can also be used as a short form of other names that begin with Leo-, such as Leonard, Leonardo, or Leopold. In Japanese, Leo or Reo (怜央) is usually a masculine given name.

The name can refer to:

People

Religious figures

Pope Leo (disambiguation), 13 popes
List of saints named Leo
Leo of Constantinople (fl. 1134–1143), Patriarch of Constantinople
Leo Rajendram Antony (1927–2012), 4th Bishop of Trincomalee
Leo Baeck (1873–1956), German rabbi, scholar, and theologian
Leo Zhedenov (1883–1959), member of the Russian apostolate

Rulers

Emperor Leo (disambiguation), six Byzantine emperors
King Leo (disambiguation), various kings and monarchs with the ruling name Leo
Leo I, Prince of Armenia (died 1140)

Scientists

Leo Esaki (born 1925), Japanese physicist and Nobel laureate
Leo Kadanoff (1937–2015), American physicist
Leó Szilárd (1898–1964), Jewish Hungarian-American physicist

In sports

Association football

Leo Beenhakker (born 1942), Dutch football manager
Leo Bosschart (1888–1951), Dutch footballer
Leo Fortune-West (born 1971), English footballer
Leo Krupnik (born 1979), Ukrainian-born American-Israeli former soccer player and current soccer coach
Leo Messi (born 1987), Argentine footballer

Other sports

Leo Baker (skateboarder) (born 1991), American skateboarder
Leo Barry (born 1977), Australian rules footballer
Leo Cantor (1919–1995), American NFL football player
Leo Chenal (born 2000), American football player
Leo Durocher (1905–1991), American baseball player and manager
Leo Klein Gebbink (born 1968), Dutch field hockey player
Leo Koloamatangi (born 1994), American football player
Leo Komarov (born 1987), Finnish ice hockey player
Leo Mazzone (born 1948), pitching coach for the Atlanta Braves and the Baltimore Orioles
Leo Monahan (journalist) (1926–2013), American sports journalist
Leo Nomellini (1924–2000), American football player in both the College and Pro Football Halls of Fame
Leo Peelen (1968–2017), Dutch track cyclist
Leo Visser (born 1966), Dutch ice speed skater
Leo van Vliet (born 1955), Dutch road bicycle racer

Artists and entertainers

Leo Arnaud (1904–1991), French-American composer
Leo de Berardinis (1940–2008), Italian stage actor and theatre director
Leo de Bever (1930–2015), Dutch architect
Leo G. Carroll (1886–1972), English actor
Leo Chiosso (1920 - 2006), Italian lyricist
Leo F. Forbstein (1892–1948), American film musical director and orchestra conductor
Leo Gorcey (1917–1969), American actor
Leo Howard (born 1997), American actor and martial artist
Leo von König (1871–1944), German painter
Leo Kottke (born 1945), American Finger-style Guitarist
Leo Ku (born 1972), Hong Kong singer and actor
Leo Rosten (1908–1997), American humorist
Leo Saussay (born 1990), Thai actor and singer
Leo Sayer (born 1948), British-born Australian pop musician
Leo Tolstoy (1826–1910), Russian novelist

Politicians

Leo von Caprivi (1831–1899), German general and Chancellor of Germany
Leo Fernando (1895–1954), Sri Lankan Sinhala businessman, Member of Parliament for Buttala Electoral District
Leo McAdam (born c. 1930), Canadian politician
Leo Parskey (1915–1994), justice of the Connecticut Supreme Court
Leo Ryan (1925–1978), California Congressman killed at Jonestown
Leo Varadkar (born 1979), Irish politician and Tánaiste

Other

Leo of Tripoli (died after 921/2), Greek renegade and admiral for the Abbasid Caliphate
Leo Africanus (c. 1494 – c. 1554?), Andalusian Berber Moorish diplomat and author
Leo Burnett (1891–1971), American advertising executive
Leo Fender (1909–1991), American inventor, maker of electric guitars
Leo Frank (1884–1915), American Jew murdered by a lynch mob
Leo Jogiches (1867–1919), Russian Marxist revolutionary
Leo Krim (2010–2012), American child killed along with his sister Lucia by their nanny
Leo Laporte (born 1956), American technology broadcaster and author
Leo Lee Tung-hai (1921–2010), Chairman of the Board of the Tung Wah Group of Hospitals from 1970–1971, businessman and philanthropist in Hong Kong
A. Leo Levin (1919–2015), American law professor
Leo Loudenslager (1944–1997), American world champion aerobatics aviator
Leo Strauss (1899–1973), American political philosopher

Fictional characters

Dr. Leo Marvin, in the 1991 American comedy film What About Bob?, played by Richard Dreyfuss
Leo Das, in the 2023 Indian action film Leo, played by Vijay
Leo Beck, hunter in the video game Identity V
Leo Tsukinaga, singer/songwriter from the franchise Ensemble Stars!
Leo Corbett (Power Rangers), on the television series Power Rangers: Lost Galaxy
Leo Demidov, protagonist of the novel Child 44
Leo, from the manga series Pandora Hearts
the title character of Ultraman Leo, a 1974 tokusatsu television series
Leo Jones (Doctor Who), on the television series Doctor Who
Leo Kliesen, a German spelunker in the Tekken series
Leo Kovalensky, from the novel We the Living by Ayn Rand
Leo McGarry, on the television series The West Wing
Leo Fitz, on the television series Agents of S.H.I.E.L.D., played by Iain De Caestecker
Leo Ross, in the 1989 American action comedy movie Speed Zone
Leo, a nickname for Leonardo from Teenage Mutant Ninja Turtles
Leo Wong, the father of Amy Wong on the television series Futurama
Leo Valdez, a son of Hephaestus from Rick Riordan's The Heroes of Olympus fantasy novel series
Leo Wagonman, one of the two main characters in the American sitcom television series George and Leo
Leo Wyatt, on the television series Charmed
Uncle Leo, on the television series Seinfeld
Leo (That '70s Show), on the television series That '70s Show, played by Tommy Chong
Leo (comics), in the Marvel universe
Leo (Yu-Gi-Oh! 5D's), in the manga series Yu-Gi-Oh!
A character in the video game series Tekken
A character in the opera Leo, the Royal Cadet
A character in the video game Final Fantasy VI
A character in Red Earth (video game) (aka Warzard)
Leo, in the American animated series Little Einsteins
Leo, in the Canadian animated series Caillou
A character in the anime and manga series Fairy Tail, who also goes by the name of "Loke"
A character in the video game Fire Emblem Fates
Leo, a character in the Doubutsu Sentai Zyuohger
Leo Lieberman, daughter of David "Micro" Lieberman and Sarah Lieberman in The Punisher, portrayed by Ripley Sobo
Leo, one of the instructors in the video game Fitness Boxing 2: Rhythm and Exercise