Preben von Ahnen (18 September 1606 – 15 November 1675) was a German-born civil servant and landowner in Norway.
Preben von Ahnen was born on the island of Rügen, off the Pomeranian coast in the Baltic Sea. He was a son of Pomeranian nobleman Staffen von Ahnen (born abt 1580) and nephew of Claus von Ahnen (ca 1560- 1628), who was a bailiff of Sem in Tønsberg in Vestfold and Eiker in Buskerud. He was the father of Iver von Ahnen (1659-1722), a Norwegian military officer who served as Governor of Romsdal.
Preben von Ahnen became a sizable landowner as a result of his two marriages. From his first marriage to Else Urne (1595-1643), he acquired Dønnagodset på Helgeland, an extensive estate located along the coast of Nordland. Through his marriage in 1657 to his second wife, Karine Iversdatter Vind (1626-1705), he became the owner of Kaupanger Hovedgård in Sogn og Fjordane.
In 1657 he established the iron foundry Ulefos Jernværk at Ulefoss in Nome, together with Ove Gjedde. He served for 20 years as baliff and district governor in Nordland, He retired from public service as Governor of Bratsberg where he had served from 1669 to 1675.