The Sibillini Mountains, or Sibylline Mountains (Italian: Monti Sibillini) are one of the major mountain groups in the Italian Peninsula, and part of the Apennines range. Most of the peaks are over 2,000 m (6,600 ft); the highest is Monte Vettore at 2,476 m (8,123 ft).

Since 1993 the area has been part of the Parco Nazionale dei Monti Sibillini (Sibillini Mountains National Park).

The present-day landscape morphology, predominantly U-shaped valleys and glacial depressions, is due to the action of glaciers during the Quaternary period.

The name Sibylline goes back to a legend about a cave in the mountains (today known as the Sibyl cave), where a male oracle and necromancer took refuge to escape Christian persecutions against paganism in the late Roman period, and who occasionally revealed secrets of the future. Necromancers and knights travelled from across Europe, after exhausting journeys, to try to obtain a prophesy.

• crested porcupine
• Eurasian eagle owl
• golden eagle
• peregrine falcon
• roe deer
• viper
• wildcat
• wolf

The small Lago di Pilato within a deep U-shaped valley below Monte Vettore, is home to a crustacean endemic to this location, Chirocephalus marchesonii.

The area contains stands of beech scattered amongst open subalpine grasslands and meadows maintained by the grazing of sheep.

• Apennines
• Geography of Italy
• Monte Ascensione

• Gentili, Bernardino (April 2002). "Note di Geomorfologia del Parco Nazionale dei Monti Sibillini". Collana dei Quaderni scientifico-divulgativi del Parco Nazionale dei Monti Sibillini. Ancona: Aniballi Grafiche.

42°49′26″N 13°16′32″E / 42.82389°N 13.27556°E / 42.82389; 13.27556