Claes is a masculine given name, a version of Nicholas, as well as a patronymic surname. It is also spelled Klas, Clas and Klaes.
Claes is a common first name in Sweden. It was also a common name in the Low countries until the 18th century, after which the spelling Klaas was largely adopted. People with the given name Claes include:
- Claes Adelsköld (1824–1907), Swedish engineer, military officer and politician
- Claes Andersson (1937–2019), Finnish psychiatrist and politician
- Claes Bang (born 1967), Danish actor and musician
- Claes van Beresteyn (1627–1684), Dutch landscape painter
- Claes Berglund (born c.1960), Swedish ski-orienteering competitor
- Claes Björklund (born 1971), Swedish musician, producer and songwriter
- Claes Michielsz Bontenbal (1575–1623), Dutch civil servant involved in a conspiracy against Maurice of Orange
- Claes Borgström (1944–2020), Swedish lawyer and politician
- Claes Compaen (1587–1660), Dutch privateer, pirate, and merchant
- Claes Cronqvist (born 1944), Swedish former footballer
- Claes Cronstedt, Swedish lawyer
- Claes Dahlbäck (born 1948), Swedish businessman
- Claes Duyst van Voorhout (fl. 1638), Dutch brewer painted by Frans Hals
- Claes Egnell (1916–2012), Swedish sport shooter
- Claes Eklundh (born 1944), Swedish artist
- Claes Elefalk (born 1959), Swedish sports agent
- Claes Elfsberg (born 1948), Swedish television journalist
- Claes Elmstedt (1928–2018), Swedish politician
- Claes Eriksson (born 1950), Swedish director, actor, comedian and composer
- Claes Fellbom (born 1943), Swedish director, writer and composer
- Claes Fornell, Swedish-born American entrepreneur
- Claes af Geijerstam (born 1946), Swedish musician, radio personality and DJ
- Claes Gill (1910–1973), Norwegian author, poet and actor
- Claes Dirksz van der Heck (1595–1649), Dutch painter
- Claes Jacobsz van der Heck (1575–1652), Dutch painter
- Claes Hellgren (born 1955), Swedish handball player
- Claes van Heussen (1598–1633), Dutch still life painter
- Claes Hylinger (born 1943), Swedish novelist, essayist, poet and literary critic
- Claes Johanson (1884–1949), Swedish wrestler
- Claes Kronberg (born 1987), Danish footballer
- Claes Lang (1690–1761), Finnish painter
- Claes Loberg (born 1970), Swedish-born Australian technology entrepreneur
- Claes Malmberg (born 1952), Swedish former footballer
- Claes Malmberg (born 1961), Swedish actor and stand-up comedian
- Claes Pietersz van der Meulen (1642–1693), Dutch glass painter
- Claes Corneliszoon Moeyaert (1592–1655), Dutch painter
- Claes Nordén (born 1993), Swedish ice hockey player
- Claes Nordin (born 1955), Swedish badminton player
- Claes Oldenburg (1929–2022), Swedish-born American pop art sculptor
- Claes Pieterszoon (1593–1674), Dutch surgeon and mayor of Amsterdam
- Claes Rålamb (1622–1698), Swedish statesman
- Claes Roxbergh (born 1945), Swedish politician
- Claes G. Ryn (born 1943), Swedish-born American political scientist
- Claes Isaacsz Swanenburg (1572–1652), Dutch painter
- Claes Tholin (1860–1927), Swedish politician
- Claes Tornberg (born 1936), Swedish rear admiral
- Claes Uggla (1614–1676), Swedish military officer
- Claes Västerteg (born 1972), Swedish politician
- Claes Jansz Visscher (1587–1652), Dutch draughtsman, engraver, mapmaker and publisher
- Claes Wersäll (1888–1951), Swedish gymnast
Claes is the 7th most common surname in Belgium (16,840 people in 1998) and the most common surname in Belgian Limburg.[1][2] In contrast, only 405 people have the surname in the Netherlands.[3] People with the last name Claes include:
- Dirk Claes (born 1959), Belgian politician
- Ernest Claes (1885–1968), Belgian author
- Gabrielle Claes, Belgian museum curator
- Georges Claes (1920–1994), Belgian racing cyclist
- Glenn Claes (born 1994), Belgian footballer
- Ian Claes (born 1981), Belgian former footballer
- Johnny Claes (1916–1956), Belgian racing driver
- Kelly Claes (born 1995), American volleyball player
- Paul Claes (born 1943), Belgian writer, poet and translator
- Virginie Claes (born 1982), Miss Belgium 2006
- Willy Claes (born 1938), Belgian politician, Secretary General of NATO 1994-1995
- Wouter Claes (born 1975), Belgian badminton player