Phibsoo Wildlife Sanctuary, Protected wildlife sanctuary in western Sarpang District, Bhutan

Phibsoo Wildlife Sanctuary is a protected area in the western part of Sarpang District, Bhutan, spanning a range of elevations from lowlands to forested hills. This variation in terrain creates different habitats within the same reserve, supporting a wide range of animal and plant life.

The reserve's forests were disturbed during the internal militia troubles of the 1990s, and the protected area only came to life in 2009. It now forms part of a biological corridor linking Jigme Singye Wangchuck and Royal Manas national parks across a national highway.

Phibsoo has no human residents, unlike Royal Manas National Park, which it otherwise resembles in wildlife. The nearest town is Phuncholing, about 50 km from the sanctuary's southwestern edge, where the only sparse population near the boundary lives. The reserve is instead known for its natural sal (Shorea robusta) forests and chital, the spotted deer also called axis.

Phibsoo has no human residents and lies about 50 km from the nearest town, Phuentsholing. It is bounded by the Sunkosh River to the west and the Sanathang River to the east, which separate it from the Indian border. Access is via a biological corridor crossing a national highway.

Phibsoo is the only protected area in Bhutan where natural sal (Shorea robusta) forests and chital (Axis axis, spotted deer) are conserved together. The reserve also shelters three species of mahseer and possibly the rare Ganges river dolphin in its rivers.