Knudtzon is a surname. Notable people with the surname include:
Birger Knudtzon (born 1936), retired Norwegian rower
Broder Knudtzon (1788–1864), Norwegian merchant, politician and benefactor
Erling Knudtzon (born 1988), Norwegian football midfielder
Hans Carl Knudtzon (1751–1823), Norwegian merchant, ship-owner and politician
Jørgen Alexander Knudtzon (1854–1917), Norwegian linguist and historian
Jørgen von Cappelen Knudtzon (1784–1854), Norwegian businessman and patron of the arts
Leif Knudtzon (1895–1925), Norwegian modern pentathlete
Nic Knudtzon (1922–2013), Norwegian telecommunications engineer
Andrew Johnson Knudtzon (c.1880s), fish business owner (cod processing), Hull and grandfather of aviator Amy Johnson
