The Battle of Valmy is the first major victory by the army of France during the Revolutionary Wars that follow the French Revolution.

The action takes place on September 20, 1792, as Prussian troops commanded by the Duke of Brunswick attempt to march on Paris.

Generals François Kellermann and Charles Dumouriez stop the advance near the northern village of Valmy in Champagne-Ardenne.

In this early part of the Revolutionary Wars—known as the War of the First Coalition—the new French government is in almost every way unproven, and thus the small, localized victory at Valmy becomes a huge psychological victory for the Revolution at large.

The outcome is thoroughly unexpected by contemporary observers—a vindication for the French revolutionaries and a stunning defeat for the vaunted Prussian army.

The victory emboldens the newly assembled National Convention to formally declare the end of monarchy in France and to establish the First French Republic.

Valmy permits the development of the Revolution and all its resultant ripple-effects, and for that it is regarded by historians as one of the most significant battles in history.