The Kőszeg Mountains [ˈkøːsɛɡ], sometimes called the Guns or Güns Mountains (German: Günser Gebirge, Hungarian: Kőszegi-hegység), are a mountain range in the Alpokalja area, the easternmost region of the Alps. The territory of the range is shared between Austria and Hungary.
Geologically, the mountains represent a Penninic window, formed from metamorphic rocks transformed about 28–31 million years ago and uplifted between 15–18 million years ago. The landscape features a main north-south ridge with multiple east-west tributary ridges, creating a distinctive pattern of parallel valleys shaped by streams flowing eastward toward the Gyöngyös.