Long-tailed Mountain Rat
Niviventer rapit
- Least concern
- Card rarity: Common
- Mammals

The long-tailed mountain rat is a species of rodent in the family Muridae. It is endemic to Borneo and found in Indonesia and Malaysia. Recorded at elevations of 940–3,360 m (3,080–11,020 ft) above sea level, it is a poorly known species but presumably common, assumed to inhabit forests and scrubland.
Classification
- Class
- Mammalia
- Order
- Rodentia
- Family
- Muridae
- Genus
- Niviventer