Johann Daniel Titius (born Johann Daniel Tietz(e), 2 January 1729 – 16 December 1796) was a German astronomer and a professor at Wittenberg. Titius was born in Konitz (Chojnice), Royal Prussia (a fief of the Crown of Poland) to Jakob Tietz, a merchant and council member from Konitz, and Maria Dorothea, née Hanow. His original name was Johann Tietz, but as was customary in the 18th century, when he became a university professor, he Latinized his surname to Titius. Tietz attended school in Danzig (Gdańsk) and studied at the University of Leipzig (1749–1752). He died in Wittenberg, Electorate of Saxony.