Francis I (German: Franz Stefan, French: François Étienne; 8 December 1708 – 18 August 1765) was Holy Roman Emperor and Grand Duke of Tuscany, though his wife effectively executed the real powers of those positions. With his wife, Maria Theresa, he was the founder of the Habsburg-Lorraine dynasty. From 1728 until 1737 he was Duke of Lorraine. Francis traded the duchy to the ex-Polish king Stanisław Leszczyński in exchange for the Grand Duchy of Tuscany as one of the terms ending the War of the Polish Succession in November 1738. The duchy and the ducal title to Lorraine and Bar passed to King Louis XV of France upon Leszczynski's death in 1766, though Francis and his successors retained the right to style themselves as dukes of Lorraine and Bar.

Francis was born in Nancy, Lorraine (now in France), the oldest surviving son of Leopold, Duke of Lorraine, and his wife Élisabeth Charlotte d'Orléans. He was connected with the Habsburgs through his grandmother Eleonor, daughter of Emperor Ferdinand III. He was very close to his brother Charles and sister Anne Charlotte.

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