Joanna of Austria (German Johanna von Österreich, Italian Giovanna d'Austria) (24 January 1547 – 11 April 1578) was born an Archduchess of Austria as the youngest daughter of Ferdinand I, Holy Roman Emperor, and Anna of Bohemia and Hungary.
By marriage, she was the Grand Princess of Tuscany and later the Grand Duchess of Tuscany.
One of her daughters was Marie de Medici, second wife of King Henry IV of France.