Christian I of Saxe-Merseburg (Dresden, 27 October 1615 – Merseburg, 18 October 1691), was the first duke of Saxe-Merseburg and a member of the House of Wettin.
He was the sixth (but third surviving) son of Johann Georg I, Elector of Saxony, and his second wife Magdalene Sibylle of Prussia.
As a younger son, Christian had little prospect of inheriting the Electorate of Saxony, and instead received from his father in 1650 the administration of the former Bishopric of Merseburg, which had been confiscated after the Reformation. He was also elected by the Chapter of the cathedral.
In a testament signed on 20 July 1652, the Elector John George I settled on an official division of the Albertine lands. Christian moved to Merseburg with his wife and children on 30 September 1653 and set up a household of his own. His court soon encompassed 150 people.
Christian took formal possession of his lands on 22 April 1657, a few months after the funeral of his father on 27 January 1657. According to the will of John George I, Christian received Merseburg and the cities of Bad Lauchstädt, Schkeuditz, Lützen, and Zwenkauand with their castles, half of the towns of Brehna, Zörbig, and Finsterwalde, and the Margraviate of Lower Lusatia, including the towns and castles of Lübben, Dobrilugk, Finsterwalde, Guben, Luckau, Calau, and Spremberg; this settlement created the Duchy of Saxe-Merseburg with Christian as its ruler.