The Duchy of Saxe-Merseburg was a duchy of the Holy Roman Empire, with Merseburg as its capital. It existed from 1656 or 1657 to 1738 and was owned by an Albertine secundogeniture of the Saxon House of Wettin.

Merseburg is a town in central Germany in southern Saxony-Anhalt, situated on the river Saale, and approximately 14 km south of Halle (Saale) and 30 km west of Leipzig. It is the capital of the Saalekreis district. It had a diocese founded by Archbishop Adalbert of Magdeburg. The University of Merseburg is located within the town. Merseburg has around 35,000 inhabitants.