The Treaty of Kiel or Peace of Kiel was concluded between the United Kingdom of Great Britain and Ireland and the Kingdom of Sweden on one side and the Kingdoms of Denmark and Norway on the other side on 14 January 1814 in Kiel. It ended the hostilities between the parties in the ongoing Napoleonic Wars, where the United Kingdom and Sweden were part of the anti-French camp while Denmark–Norway was allied to France.

Denmark–Norway was a 16th-to-19th-century multi-national and multi-lingual real union consisting of the Kingdom of Denmark, the Kingdom of Norway, the Duchy of Schleswig, and the Duchy of Holstein. The state also claimed sovereignty over three historical peoples: Frisians, Gutes and Wends. Denmark–Norway had several colonies, namely the Danish Gold Coast, the Nicobar Islands, Serampore, Tharangambadi, and the Danish West Indies. The union was also known as the Dano-Norwegian Realm, Twin Realms (Tvillingerigerne) or the Oldenburg Monarchy (Oldenburg-monarkiet).