Sapo National Park, National park in Sinoe County, Liberia.

Sapo National Park is a national park in Sinoe County, Liberia, covering 1,804 km2 east of the Sinoe River and south of the Putu Mountains. It protects lowland rainforest within the Upper Guinean forest ecosystem, with a canopy of tall trees and a network of streams. The park is the country's largest protected rainforest area and holds West Africa's second-largest block of primary tropical rainforest after Taï National Park in Côte d'Ivoire.

The park was officially established in 1983, making it Liberia's first protected area. This designation began the country's formal conservation efforts.

The park takes its name from the Sapo (or Sao) tribe living in the area. From 1977 Alexander Peal headed Liberia's Division of Wildlife and National Parks, and USAID-funded initiatives made villagers around Sapo stakeholders in its protection until the 1990s. During the civil war the park sheltered small groups who scavenged for food and hunted bushmeat to survive.

Visitors need permission from authorities and must always be accompanied by a guide. Be prepared for muddy trails and heavy rainfall, especially during wet months when conditions become difficult.

Sapo was named after the Sapo (or Sao) tribe living in the area, and its boundaries were drawn by the Division of Wildlife and National Parks with the WWF, IUCN and the Peace Corps. A 1989 wildlife rehabilitation and orphanage facility, supported by Friends of Animals, was destroyed during the First Liberian Civil War.