Mortagne (French pronunciation: [mɔʁtaɲ] ⓘ) is a commune in the Vosges department in Grand Est in northeastern France.

The commune is positioned on undulating lower slopes of the Vosges Mountains.

The commune is crossed by the little River Mossoux, a tributary of the Mortagne which itself feeds into the Meurthe.

Much of the valley here remains wild and uncultivated: the last farm on the route to the forest is called 'The End of the World'.

For many years there was a widespread belief that the name was of Roman origin, related to the name 'Mauritania', being a reference to an encampment of a Moorish regiment during the closing centuries of the Roman Empire period: this belief is now discredited.