Kristoffer Throndsen (c. 1500–1565), posthumously also with the family name Rustung, was a squire, admiral, feudal overlord in Norway and Denmark, privateer captain and pirate. Kristoffer served Archbishop Olav Engelbrektsson, the interregnum leader of Norway, in the last years of the Kalmar Union.
Kristoffer is famous for playing a role in the last years before the Reformation in Norway, first as the head of the national fleet, defending Norway from attacking Danish ships; and also as the murderer of Vincent Lunge, a Danish nobleman sent to Bergen in 1537 to enforce the Danish annexation of Norway by the King of Denmark Christian III. This dramatic moment in Norwegian history is memorialized today in an annual "midnight opera" sponsored by the Norwegian Ministry of Culture. Titled Olav Engelbrektsson, it takes place on the premises of the castle, outside Trondheim.
Kristoffer appealed for pardon from Christian III, probably for the murder but also for his piracy of the Norwegian coast under foreign flags, under which he attacked Danish ships and installations in Norway after 1536. He was granted a post under the Danish crown, which badly needed a naval leader. He served for several years as an admiral in the Danish Navy, and later in Copenhagen as a Royal Danish Consul to the King.
His most famous child was Anna Throndsen, known in Norway as "the Scottish Lady" (Skottefruen). Anna is famous in modern-day Norway, for her days in the court of Mary Queen of Scots, during her marriage to James Hepburn, Lord Bothwell.