The Border Protection Corps (Polish: Korpus Ochrony Pogranicza, KOP) was a military formation of the Second Polish Republic that was created in 1924 to defend the country's eastern borders against armed Soviet incursions and local bandits. Other borders were under the jurisdiction of a separate, regular Border Guard state security agency.

Though the corps was part of the Polish Army, it was commanded directly by the Ministry of Internal Affairs rather than the Ministry of National Defence. It consisted of elite soldiers from all parts of Poland. Initially KOP comprised 6 brigades and 5 regiments, each guarding part of the borders with the Soviet Union. KOP ceased to exist with the fall of Poland in September 1939.