The Grosses Wannenhorn is a 3906-metre mountain in the Bernese Alps, in the Swiss canton of Valais near the village of Fiesch.

The east side of the Grosses Wannenhorn is heavily glaciated, while the west side is a steep slope intermittently broken by ice fields.

In the southeast, there lies the rocky sub-peak Kleines Wannenhorn (3707 m).

The mountain was first climbed by Gottlieb Studer and team in 1864.

This article about a mountain, mountain range, or peak located in Valais is a stub.