Achille Fontanelli (8 November 1775 – 22 July 1838) was an Italian nationalist and Napoleonic general. Born into a low-ranking noble family, he took service with a pro-French Italian military unit in 1797. He was captured in 1799 but was repatriated in time to serve in the Marengo Campaign in 1800. He was promoted to general officer in 1804 and in the 1809 war he led an Italian division in several major battles. After serving as Minister of War to Eugène de Beauharnais, he was tapped to command a division in the 1813 campaign. After the collapse of Napoleon's empire in 1814, he took service with the Austrian Empire.