Ketelaar or Ketelaars is a Dutch surname. Notable people with the surname include:
Digna Ketelaar (born 1967), Dutch tennis player Hanneke Ketelaars (born 1974), Dutch tennis player James Edward Ketelaar (born 1957), American scholar and historian Jan Ketelaar (1908–2001), Dutch chemist and author Leo Ketelaars (1913–1992), Dutch violinist, operatic baritone, opera manager and academic voice teacher Sander van Doorn (real name Sander Ketelaars; born 1979), Dutch DJ and record producer
See also De Ketelaere