Leopold of Anhalt-Köthen was a German prince of the House of Ascania and ruler of the principality of Anhalt-Köthen. Today, he is best remembered for employing Johann Sebastian Bach as his Kapellmeister between 1717 and 1723.

Anhalt-Köthen was a principality of the Holy Roman Empire ruled by the House of Ascania. It was created in 1396 when the Principality of Anhalt-Zerbst was partitioned between Anhalt-Dessau and Anhalt-Köthen. The first creation lasted until 1562, when it fell to Prince Joachim Ernest of Anhalt-Zerbst, who merged it into the reunited Principality of Anhalt.