Diderik or Didrik is a Norwegian male given name. In North Germanic languages, the native form would be Tjodrik, but Diderik and Didrik have been loaned from Low German and are now a common name in Norway. It may also be a variant of the related Dutch name Diederik. People with the name include:

• Diderik Batens (born 1944), Belgian logician and epistemologist at the University of Ghent

• Diderik Bøgvad (1792–1857), Norwegian politician

• Diderik von Cappelen (1761–1828), Norwegian merchant and politician

• Diderik Hegermann Rye (1832–1914), Norwegian civil servant

• Diderik Hegermann (1763–1835), Norwegian councillor of state and Minister of the Army

• Diderik Schnitler (born 1946), Norwegian businessperson

• Diderik Iversen Tønseth (1818–1893), Norwegian politician for the Liberal Party

• Diderik Wagenaar (born 1946), Dutch composer and musical theorist

• Didrik Pining (c. 1430–1491), German privateer, nobleman and governor of Iceland