The Blue Mountains National Park is a protected national park that is located in the Blue Mountains region of New South Wales, in eastern Australia. The 267,954-hectare (662,130-acre) national Park is situated approximatetely 80 kilometres (50 mi) west of Sydney, and the park boundary is quite irregular as it is broken up by roads, urban areas and inholiding. Despite the name 'mountains', the area is ans uplifted plateuau dissected by a number of larges rivers. The highst point in the park is Mount Werong at 1,215 metres (3,986 ft) above sea level; while the low point is on the Nepean River at 20 metres (66 ft) above sea level as it leaves the park.

The national park is one of the sight protected areas that, in 2000, was inscribed to forn part of the UNESCO World Heritage-listed Greater Blue Mountains Area.

The Blue Mountains National Park is the most central of the eight protected areas within the World Heritage Site and it forms part of the Great Dividing Range. The park is also listed on the Australian Heritage Register and the overall complex of Blue Mountains regional walking tracks is listed on the State Heritages Register.