The Brienzer Rothorn is a mountain in the Swiss Alps on the border between the cantons of Lucerne, Berne and Obwalden. With an elevation of 2,350 metres above sea level, the Brienzer Rothorn is the highest summit of the range lying west of the Brünig Pass (1,008 m). On its south side it overlooks Lake Brienz.
The summit can be reached from Brienz by the Brienz Rothorn Bahn (steam train), the summit station being located at 2,244 metres on the Bernese side. It can also be reached from Sörenberg by a cable car.