Gaarder is a Norwegian surname. Notable people with the surname include:
Inger Margrethe Gaarder (1926–1993), Norwegian writer Jon Atle Gaarder (1934–2020), Norwegian diplomat Jostein Gaarder (born 1952), Norwegian writer Mikkel Gaarder, Norwegian Paralympic athlete Ole P. Gaarder (1844-1927), American politician and farmer Peder Krabbe Gaarder (1814–1883), Norwegian jurist and political theorist Shabana Rehman Gaarder (born 1976), Norwegian comedian and writer Torbjørn Gaarder (1885–1970), Norwegian chemist