Legio vigesima Valeria Victrix, in English Twentieth Victorious Valeria Legion was a legion of the Imperial Roman army.
The origin of the Legion's name is unclear and there are various theories, but the legion may have gained its title Valeria Victrix from a victory it achieved during the Great Illyrian revolt under the command of the general Marcus Valerius Messalla Messallinus.
The legion had a boar as its emblem.
The legion was probably founded shortly after 31 BC by the emperor Augustus.
XX Valeria victrix was probably part of the large Roman force that fought in the Cantabrian Wars in Hispania from 25 to 19 BC.
The legion then moved to Burnum in Illyricum at the beginning of the Pannonian uprising (Bellum Batonianum) in AD 6. It is recorded operating against the Marcomanni in AD 6 in the army of Tiberius.
In Illyria they were led by the governor of Illyricum, Marcus Valerius Messalla Messallinus, who may have given his clan (gens) name Valeria to the legion. Although understrength, they managed to defeat the rebels led by Bato of the Daesitiates. In one battle the legion cut through the enemy lines, was surrounded, and cut its way out again.
After the disaster of Varus in AD 9, XX Valeria Victrix moved to Germania Inferior and was based at Oppidum Ubiorum, then moved to Novaesium at the site of modern Neuss during Tiberius' reign.