The Battle of Lugdunum, also called the Battle of Lyon, is fought on February 19, 197 at Lugdunum (modern Lyon, France), between the armies of the Roman Emperor Septimius Severus and of the Roman usurper Clodius Albinus.

Severus' victory finally establishes him as the sole emperor of the Roman Empire.The historian Cassius Dio places the number involved as 300,000, or 150,000 on either side of the battle.

This figure has been disputed, as this is approximately three-quarters of the total number of soldiers present throughout the Roman Empire at this time.

However, it is widely accepted that the total number of soldiers and support personnel involved exceeded 100,000, and could well have come close to half the 300,000 figure Dio gives.