Johann Gottlieb Stephanie the Younger (19 February 1741 – 23 January 1800) was an Austrian playwright, director and librettist, most famously to Mozart.
Stephanie was born in Breslau, Prussia. He was taken prisoner by the Austrian forces in the Battle of Landeshut (1760) in the Seven Years' War. After nine months of imprisonment in Villach, he joined the Imperial Army and went to Vienna after the war ended. He was appointed to head the National Singspiel, a favourite project of Emperor Joseph II.