The montane guinea pig (Cavia tschudii) is a species of caviid rodent found in the Andes in South America.

[3] The montane guinea pig is a medium-sized species, growing to a total length of 247 mm (9.7 in).

Its range extends from Peru southward to the Tarapacá Region of Chile and the Tucumán Province of Argentina.

It lives in moist habitats with rocks and coarse vegetation, making runways through the foliage.

Litter size ranges from one to four, and the young grow quickly, becoming independent at 2 months of age.