Franz Xavier of Saxony (Polish: Ksawery Saski) (25 August 1730 – 21 June 1806) was a Saxon prince and member of the House of Wettin.

In October 1765, Franz Xavier performed in the name of the young Elector a formal renunciation of the Polish Crown in favor of Stanislaus Poniatowski, as was required by the treaty signed between Prussia and Russia on 11 April 1764.

In Dresden on 9 March 1765 Franz Xavier married morganatically an Italian lady-in-waiting to his sister-in-law, the Dowager Electress, the contessa Maria Chiara Spinucci.

In 1769, Franz Xavier moved his family to France, the home of his younger sister, the Dauphine Marie-Josèphe, who had died two years earlier.

During their marriage, Franz Xavier and Maria Chiara had ten children — known as counts and countesses of Lusatia (de: Graf/Gräfin von der Lausitz) — but only six survived to adulthood: