Białowieża National Park (Polish: Białowieski Park Narodowy) is a national park in Podlaskie Voivodeship, in Eastern Poland adjacent to the border with Belarus. The total area of the park is 105.2 square kilometres (40.6 sq mi). It is located 62 km (39 mi) southeast of Białystok (Poland). It is known for the protection of the best preserved part of the Białowieża Forest, Europe's last temperate primaeval forest fragment that once allegedly stretched across the European Plain. It is home to the world's largest population of European bison (Polish: żubr), the continent's heaviest land animals. The border between the two countries runs through the forest, the Belovezhskaya Pushcha National Park is adjacent on the Belarus side of the border. There is a border crossing for hikers and cyclists within the forest. According to one study, the park brings in tourist revenues of about 72 million zloty per year.

The characteristic feature of the park is its biological diversity. Białowieża National Park is the only Polish natural property designated by UNESCO as a World Heritage Site. The park is the most important – central zone of Białowieża Forest Biosphere Reserve.