Atlantic Forest South-East Reserves, Nature reserve and UNESCO World Heritage Site in São Paulo and Paraná, Brazil.

Atlantic Forest South-East Reserves comprise multiple protected areas with coastal islands, mountain slopes, wetlands, and dense forest regions across southeastern Brazil. The reserve system protects different types of woodland and habitats spread across the landscape.

Large portions of the Atlantic Forest were cleared and destroyed during the 20th century. The area received UNESCO World Heritage status in 1999 to protect the remaining forest sections from further loss.

The reserves lie in the Atlantic Forest, of which about 7% of the original cover remains, mostly in this south-east region. The name Mata Atlântica refers to the coastal rainforest that runs along Brazil's Atlantic seaboard. The 25 protected areas were grouped under one UNESCO listing in 1999.

The reserve can be accessed through Intervales State Park, which provides accommodation and guided tours. Visitors should prepare for humid conditions and uneven terrain since this is a mountain forest in a tropical region.

The golden lion tamarin Leontopithecus caissara was first described by science only in 1990, and it lives in these forests. The reserve also shelters jaguars, otters and anteaters among its 120 mammal species, alongside some 350 bird species.