| Allaine | |
| Name Other: | l'Allan (m, lower course) |
| Map: | Allaine.png |
| Source1 Coordinates: | 47.4294°N 7.2304°W |
| Source1 Elevation: | 598m (1,962feet) |
| Mouth Coordinates: | 47.4785°N 6.7597°W |
| Mouth Elevation: | 335m (1,099feet) |
| Subdivision Type1: | Countries |
| Length: | 65km (40miles) |
| Basin Size: | 322km2 |
The Allaine (French: l'Allaine in French pronounced as /lalɛn/ (f), in its lower course l'Allan in French pronounced as /lalɑ̃/ (m), (German: Hall) is a 65 km long river in northwestern Switzerland and eastern France. Its source is above the village Charmoille, in the Swiss Jura mountains. Downstream from its confluence with the Bourbeuse and the Canal du Rhône au Rhin, near Méziré, it is called the Allan. It is a right tributary of the Doubs, which it joins a few km downstream from Montbéliard, where it takes the Savoureuse with it, a river with its sources in the southern Vosges.
The Allaine/Allan flows through the following cantons, departments and towns: