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 (b. 1937), Finnish psychiatrist and politician
Claes van Beresteyn (1627–1684), Dutch landscape painter
Claes Berglund (b.~1960), Swedish ski-orienteering competitor
Claes Björklund (b. 1971), Swedish musician, producer and songwriter
Claes Michielsz Bontenbal (1575–1623), Dutch civil servant involved in a conspiracy against Maurice of Orange
Claes Borgström (b. 1944), Swedish lawyer and politician
Claes Compaen (1587–1660), Dutch privateer, pirate, and merchant
Claes Cronqvist (b. 1944), Swedish footballer
Claes Cronstedt, Swedish lawyer
Claes Dahlbäck (b. 1948), Swedish businessman
Claes Egnell (1916–2012), Swedish sport shooter
Claes Eklundh (b. 1944), Swedish artist
Claes Elefalk (b. 1959), Swedish sports agent
Claes Elfsberg (b. 1948), Swedish television journalist
Claes Elmstedt (b. 1928), Swedish politician
Claes Eriksson (b. 1950), Swedish director, actor, comedian and composer
Claes Fellbom (b. 1943), Swedish director, writer and composer
Claes Fornell, Swedish-born American entrepreneur
Claes af Geijerstam (b. 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 (b. 1955), Swedish handball player
Claes van Heussen (1598–1633), Dutch still life painter
Claes Hylinger (b. 1943), Swedish novelist, essayist, poet and literary critic
Claes Johanson (1884–1949), Swedish wrestler
Claes Kronberg (b. 1987), Danish footballer
Claes Lang (1690–1761), Finnish painter
Claes Loberg (b. 1970), Swedish-born Australian technology entrepreneur
Claes Malmberg (b. 1952), Swedish footballer
Claes Malmberg (b. 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 Nobel (b. 1930), Swedish humanitarian and environmentalist
Claes Nordén (b. 1993), Swedish ice hockey player
Claes Nordin (b. 1955), Swedish badminton player
Claes Oldenburg (b. 1929), Swedish-born American pop art sculptor
Claes Pieterszoon (1593–1674), Dutch surgeon and mayor of Amsterdam
Claes Rålamb (1622–1698), Swedish statesman
Claes Roxbergh (b. 1945), Swedish politician
Claes G. Ryn (b. 1943), Swedish-born American political scientist
Claes Isaacsz Swanenburg (1572–1652), Dutch painter
Claes Tholin (1860–1927), Swedish politician
Claes Uggla (1614–1676), Swedish military officer
Claes Västerteg (b. 1972), Swedish politician
Claes Jansz Visscher (1587–1652), Dutch draughtsman, engraver, mapmaker and publisher
Claes Wersäll (1888–1951), Swedish gymnast
Claës Fredrik Hornstedt (1758–1809), Swedish naturalist, taxonomist and illustrator
Claës König (1885–1961), Swedish noble man and horse rider
Claës Palme (1917–2006), Swedish maritime lawyer
Claës Rundberg (1874–1958), Swedish sport shooter
Claes is the 7th most common surname in Belgium (16,840 people in 1998) and the most common surname in Belgian Limburg. In contrast, only 405 people have the surname in the Netherlands. People with the last name Claes include:
Dirk Claes (b. 1959), Belgian politician
Ernest Claes (1885–1968), Belgian author
Gabrielle Claes, Belgian museum curator
Georges Claes (1920–1994), Belgian racing cyclist
Glenn Claes (b. 1994), Belgian footballer
Ian Claes (b. 1981), Belgian footballer
Johnny Claes (1916–1956), Belgian racing driver
Paul Claes (b. 1943), Belgian writer, poet and translator
Virginie Claes (b. 1982), Miss Belgium 2006
Willy Claes (b. 1938), Belgian politician, Secretary General of NATO 1994-1995
Wouter Claes (b. 1975), Belgian badminton player
