3rd Mountain Brigade (3. Brygada Gorska) was a unit of the Polish Army, which took part in the Polish September Campaign in 1939. Commanded by Colonel Jan Stefan Kotowicz, it was part of Operational Group “Slovakia” of Armia Karpaty. It guarded southern Polish border from Gorlice to the Bieszczady Mountains. On September 10, the Brigade fought the aggressors in the area of Sanok, but was forced to retreat towards Turka. Between September 16 and 17 it attacked the Germans in Sambor, and three days later remnants of the unit left Poland for Hungary.