Diderik von Cappelen (21 June 1761 – 3 April 1828) was a Norwegian wholesaler, merchant, shipowner, estate owner and politician in 1814.

He was one of the sons of the wholesaler, timber merchant and ship owner Diderich von Cappelen (1734–1794) and his first wife Petronelle Pedersdatter Juel (1737–1785).

[clarification needed] Cappelen, Anker, Arnesen, Blom, Borgfjord, Finne, Flood, Hofgaard, Lund, Løvenskiold, Nicolaisen, Norby, Prebensen, Skråmestø, Wildhagen and Aall, are several business people, estate owners, politicians, lawyers etc.

Cappelen was educated in his father's business, after being in 1779–80 at Kingswood School outside Bristol where he also met John Wesley.

Diderik von Cappelen was a successful businessman continuing and expanding the family business.