Klaes is a given name and surname. Notable people with the surname include:
Klaes Karppinen (1907–1992), Finnish cross-country skier Lara Klaes (born 1997), German politician Ulrich Klaes (born 1946), German field hockey player
Fictional characters with the name include: Klaes Ashford, a character in The Expanse (TV series)