The Treaty of Roskilde was signed on February 26, 1658 in the Danish city Roskilde, whereby the king of Denmark-Norway sacrificed nearly half his territory to save the rest. He was forced to cede the Danish provinces of Terra Scania and the Norwegian provinces of Trondheim and Bahusia to Sweden upon Charles X Gustav of Sweden's occupation of Zealand, which began with the landing on February 11, 1658. But this was not enough for the king, and at the Council held at Gottorp on July 7, Charles X Gustav resolved to wipe from the map of Europe an inconvenient rival, and without any warning, in defiance of all international equity, let loose his veterans upon Denmark-Norway a second time.

Following the attack on Copenhagen and the city's successful defence, and the reconquest by Norwegian forces of Trondheim, the Treaty of Copenhagen in 1660 restored that province to Norway, and the island of Bornholm to Denmark.

The treaty of Roskilde was preceded by the Treaty of Taastrup on February 18, 1658.