Bremen-Verden, formally the Duchies of Bremen and Verden (German: Herzogtümer Bremen und Verden), are two territories and immediate fiefs of the Holy Roman Empire, which emerge and gain Imperial immediacy in 1180.

By their original constitution they are prince-bishoprics of the Archdiocese of Bremen and Bishopric of Verden.In 1648, both prince-bishoprics are secularised, meaning that they are transformed into heritable monarchies by constitution, and from then on both the Duchy of Bremen and the Duchy of Verden are always ruled in personal union, initially by the royal houses of Sweden, the House of Vasa and the House of Palatinate-Zweibrücken, and later by the House of Hanover.With the dissolution of the Holy Roman Empire in 1806, Bremen-Verden's status as fiefs of imperial immediacy becomes void; as they had been in personal union with the neighboring Kingdom of Hanover, they are incorporated into that state.