The river Eaulne (French pronunciation: [o(l)n]) is one of the rivers that flow from the plateau of the eastern Pays de Caux in the Seine-Maritime département of Normandy in northern France. It is 45.5 km (28.3 mi) long.

The Eaulne's source is at Mortemer. It then flows northwestwards through Sainte-Beuve-en-Rivière, Saint-Germain-sur-Eaulne, Londinières, Douvrend, Envermeu, turning westward at Bellengreville and on to Ancourt, Martin-Église and joins the river Arques at Arques-la-Bataille.

• French water management scheme