Venutius was a king of the Brigantes, a group living in northern Britain during the time the Romans took over the region in the 1st century. Some people believe he might have been part of the Carvetii, another group that may have been connected to the Brigantes.

Historians first learned about Venutius when he became the husband of Cartimandua, the queen of the Brigantes, around the year 51 AD. After a British leader named Caratacus was defeated by a Roman general named Publius Ostorius Scapula in Wales, he fled to the Brigantes. However, Cartimandua handed Caratacus over to the Romans. At this time, the Brigantes were not fully controlled by Rome, but the Roman writer Tacitus said Cartimandua and Venutius were loyal to Rome and protected by Roman power. After Caratacus was captured, Venutius became a leading figure in fighting against the Romans. Cartimandua later grew tired of Venutius and married his armor-bearer, Vellocatus, giving him the title of king instead of Venutius. At first, Venutius tried to remove his ex-wife from power, but later he turned his focus against the Romans. The Romans supported Cartimandua, and Venutius’s rebellion was defeated by a Roman general named Caesius Nasica during the rule of Aulus Didius Gallus, who governed Britain from 52 to 57 AD.

When the Roman Empire faced a period of instability known as the "Year of the Four Emperors," Venutius rebelled again in 69 AD. Cartimandua asked the Romans for help, but they could only send supporting forces. Cartimandua was forced to leave, and Venutius took control of the kingdom.

This second rebellion may have caused larger problems for the Romans. The Roman writer Tacitus said that after becoming emperor, Vespasian had to "recover" Britain. He also mentioned that Britain was left without strong Roman control during the Year of the Four Emperors, though some believe this might refer to later efforts by another Roman general, Agricola, to conquer parts of northern Britain (Scotland).

What happened to Venutius after Vespasian became emperor is unknown. A Roman general named Quintus Petillius Cerialis, who ruled Britain from 71 to 74 AD, fought against the Brigantes, but they were not fully controlled for many years. Another Roman general, Agricola, who ruled from 78 to 84 AD, also fought in the area of the Brigantes. Both a Roman poet named Juvenal and a Greek writer named Pausanias mentioned fighting against the Brigantes in the early part of the 2nd century AD.