Frederick III (; 18 March 1609 – 9 February 1670) was king of Denmark and Norway from 1648 until his death. He also governed under the name Frederick II as diocesan administrator (colloquially referred to as prince-bishop) of the Prince-Bishopric of Verden (1623–29 and again 1634–44), and the Prince-Archbishopric of Bremen (1635–45).