The Abert's Squirrel or Tassel-eared Squirrel (Sciurus aberti) is a tree squirrel that is native to the Rocky Mountains from United States to Mexico, with concentrations found in Arizona, New Mexico, and Durango.

Abert's squirrels are 46-58 cm long with a tail of 19-25 cm. They are strictly diurnal. A number of subspecies have been described including the Kaibab Squirrel.

The Abert's squirrel does not store its food like other North American squirrels. The vast majority of the squirrel's diet consists of parts of the ponderosa pine. Feeding on the tree's seeds and buds in the warmer months, it depends on the inner bark of the tree for nourishment in the wintertime. Consequently, Abert's squirrels are found in coniferous forests with large populations of ponderosa pines.