| Conventional Long Name: | Praetorian prefecture of the Gauls |
| Common Name: | Prefecture of Gaul |
| Subdivision: | Praet. Prefecture |
| Nation: | the Western Roman Empire |
| Era: | Late Antiquity |
| Capital: | Augusta Treverorum (until 395/407) Arelate (from 395/407) |
| Image Map Caption: | Praetorian Prefectures of the Roman Empire (395) |
| Life Span: | 337-477 510-536 |
| Year Start: | 337 |
| Year End: | 536 |
| Event End: | Fall of Provence to the Franks |
| Event1: | Conquest of Provence by the Visigoths |
| Date Event1: | 477 |
| Event2: | Re-established by the Ostrogoths |
| Date Event2: | 510 |
| Political Subdiv: | Diocese of Gaul Diocese of Britain Diocese of Spain Diocese of the Seven Provinces |
The Praetorian Prefecture of Gaul (Latin: praefectura praetorio Galliarum) was one of four large prefectures into which the Late Roman Empire was divided.
The prefecture was established after the death of Constantine I in 337, when the empire was split up among his sons and Constantine II received the rule of the western provinces, with a praetorian prefect as his chief aide. The prefecture comprised not only Gaul, but also of Roman Britain, Spain, and Mauretania Tingitana in Africa Proconsulare. Its territory overlapped considerably with what was once controlled by the short-lived Gallic Empire in the 260s.
After the permanent partition of the Empire in 395 into West and East spheres of control, the prefecture of Gaul continued to belong to the Western Roman Empire. Augusta Treverorum (present-day Trier in Germany) served as the prefecture's seat until 407 (or, according to other estimates, in 395), when it was transferred to Arelate (Arles).
The prefecture continued to function until 477, when the last areas under its control were seized by the Visigoths after the abolition of the Western imperial government of Ravenna in the previous year.
In 510, the Ostrogoth king Theodoric the Great re-established the prefecture in the small part of Gaul (the Provence) that he had just conquered, with headquarters again at Arelate. This short lived revival lasted until the area was in turn conquered by the Franks in 536, while the Ostrogoths were occupied by the East Roman invasion of Italy.