Transalpine Gaul was a Roman province whose name was chosen to distinguish it from Cisalpine Gaul. Transalpine means "that side of the Alps", while Cisalpine would mean "this side of the Alps". Cisalpine Gaul was on the east of the Alps range, while Transalpine Gaul was to the west. Together, the regions made up the region of Gaul, which was called Gallia by the Romans. The region that Transalpine Gaul contained is now most of France. Cisalpine Gaul included areas in France and Northern Italy.

The Latin name for this province was Gallia Transalpina. It became a Roman province in 121 BC. Later it was renamed Gallia Narbonensis, after its capital the Roman colony of Narbo Martius (Narbonne), which was founded on the coast in 118 BC.