Brecon Beacons National Park, officially named Bannau Brycheiniog National Park, is a national park in Wales. It is named after the Brecon Beacons, the mountain range at its centre. The national park includes the highest mountain in South Wales, Pen y Fan, which has an elevation of 886 metres (2,907 ft).

The national park has a total area of 1,344 square kilometres (519 sq mi). The Brecon Beacons and Fforest Fawr uplands form the central section of the park. To the east are the Black Mountains, which extend beyond the national park boundary into England, and to the west is the similarly named but distinct Black Mountain range. These ranges share much of the same basic geology, the southerly dip of the rock strata leading to north-facing escarpments. The highest peak of the Black Mountains is Waun Fach (811 metres (2,661 ft)), and Fan Brycheiniog (802.5 metres (2,633 ft)) is the highest of the Black Mountain.

The park was founded in 1957 and is the third and most recently designated national park in Wales, after Snowdonia (Eryri) and the Pembrokeshire Coast. It is visited by approximately 4.4 million people each year.