The Battle of Ostrach, also called the Battle by Ostrach, occurred on 20–21 March 1799. It was the first non-Italy-based battle of the War of the Second Coalition. The battle resulted in the victory of the Austrian forces, under the command of Archduke Charles, over the French forces, commanded by Jean-Baptiste Jourdan.

Archduke Charles Louis John Joseph Laurentius of Austria, Duke of Teschen was an Austrian field-marshal, the third son of Emperor Leopold II and his wife, Maria Luisa of Spain. He was also the younger brother of Francis II, Holy Roman Emperor. He was epileptic, but achieved respect both as a commander and as a reformer of the Austrian army. He was considered one of Napoleon's more formidable opponents and one of the greatest generals of the French Revolutionary and Napoleonic Wars.