Septimania is a historical region in modern-day southern France. It referred to the western part of the Roman province of Gallia Narbonensis that passed to the control of the Visigoths in 462, when Septimania was ceded to their king, Theodoric II. During the Early Middle Ages, the region was variously known as Gallia Narbonensis, Gallia, or Narbonensis. The territory of Septimania roughly corresponds with the modern French former administrative region of Languedoc-Roussillon that merged into the new administrative region of Occitanie. In the Visigothic Kingdom, which became centred on Toledo by the end of the reign of Leovigild, Septimania was both an administrative province of the central royal government and an ecclesiastical province whose metropolitan was the Archbishop of Narbonne. Originally, the Goths may have maintained their hold on the Albigeois, but if so it was conquered by the time of Chilperic I. There is archaeological evidence that some enclaves of Visigothic population remained in Frankish Gaul, near the Septimanian border, after 507.

Gallia Narbonensis was a Roman province located in what is now Occitania and Provence, in Southern France. It was also known as Provincia Nostra, because it was the first Roman province north of the Alps, and as Gallia Transalpina, distinguishing it from Cisalpine Gaul in Northern Italy. It became a Roman province in the late 2nd century BC. Gallia Narbonensis was bordered by the Pyrenees Mountains on the west, the Cévennes to the north, the Alps on the east, and the Gulf of Lion on the south; the province included the majority of the Rhone catchment. The western region of Gallia Narbonensis was known as Septimania. The province was a valuable part of the Roman Empire, owing to the Greek colony and later Roman Civitas of Massalia, its location between the Spanish provinces and Rome, and its financial output.