Sondernach is a commune in the Haut-Rhin département in Grand Est in north-eastern France.

Located in the parc naturel régional des Ballons des Vosges, the village of Sondernach shares with Mittlach the benefit of being situated on the slopes of a large valley watered by one of the streams forming the river Fecht.

It could be from der Sonne nahe meaning "near the Sun", or zum sundern Ach meaning "near the south stream", Sondernach being the furthest south village in the valley.

From 1287, the village was made part of the valley community grouping Munster and the ten communes of the Fecht.

It was destroyed during the First World War, during the battle of Metzeral, in June 1915.