Austerlitz, Battle of December 2, 1805, a battle fought between the French under Napoleon on one side and the Russians and Austrians on the other. It was one of Napoleon's most brilliant victories; his defeat of the Russians and Austrians broke up a coalition of European nations (the Third Coalition—Great Britain, Austria, Russia, and Sweden) opposing him and made him master of Central Europe. Also, it enabled him to dissolve the Holy Roman Empire and organize the Germanies into a confederation.

The battle was fought on a plateau near the town of Austerlitz in what is now the Czech Republic. The French army of some 70,000 faced a combined Russian and Austrian army of 82,500. The allies expected soon to double their forces, but Napoleon tricked them into battle and crushed them. The French lost about 6,800 men, the allies about 27,000.

Austerlitz is sometimes called the Battle of the Three Emperors, since Napoleon I of France, Alexander I of Russia, and Francis II of the Holy Roman Empire were present.