The Battle of Winterthur (May 27, 1799) is an important action between elements of the Army of the Danube and elements of the Habsburg army, commanded by Friedrich Freiherr von Hotze, during the War of the Second Coalition, part of the French Revolutionary Wars.

The small town of Winterthur lies eighteen kilometers (eleven miles) northeast of Zürich, in Switzerland.

Because of its position at the junction of seven roads, the army that holds the town controls access to most of Switzerland and points crossing the Rhine into southern Germany.

Although the forces involved are small, the ability of the Austrians to sustain their eleven-hour assault on the French line results in the consolidation of three Austrian forces on the plateau north of Zürich, leading to the French defeat a few days later.

By mid-May 1799, the Austrians have wrested control of parts of Switzerland from the French as forces under the command of Hotze and Count Heinrich von Bellegarde push them out of the Grisons.

After defeating Jean-Baptiste Jourdan's twenty-five thousand man Army of the Danube at the battles of Ostrach and Stockach, the main Austrian army, under command of Archduke Charles, crosses the Rhine at the Swiss town of Schaffhausen and prepares to unite with the armies of Hotze and Friedrich Joseph, Count of Nauendorf, on the plains surrounding Zürich.

The French Army of Helvetia and the Army of the Danube, now both under the command of André Masséna, seek to prevent this merger.

Masséna sends Michel Ney and a small mixed cavalry and infantry force from Zürich to stop Hotze's force at Winterthur.

Despite a sharp contest, the Austrians succeeds in pushing the French out of the Winterthur highlands, although both sides take high casualties.

Once the union of the Habsburg armies takes place in early June, Archduke Charles attacks French positions at Zürich and forces the French to withdraw beyond the Limmat.