The Principality of Lüneburg was a territorial division of the Duchy of Brunswick-Lüneburg within the Holy Roman Empire, immediately subordinate to the emperor. It existed from 1269 until 1705 and its territory lay within the modern-day state of Lower Saxony in Germany. The principality was named after its first capital, Lüneburg, which was ruled jointly by all Brunswick-Lüneburg lines until 1637. From 1378, the seat of the principality was in Celle. It lost its independence in 1705 when it was annexed by the Electorate of Brunswick-Lüneburg, but retained its vote in the Reichstag as Brunswick-Celle.

The Duchy of Brunswick-Lüneburg, or more properly the Duchy of Brunswick and Lüneburg, was a historical duchy that existed from the late Middle Ages to the Late Modern era within the Holy Roman Empire, until the year of its dissolution. The duchy was located in what is now northwestern Germany. Its name came from the two largest cities in the territory: Brunswick and Lüneburg.