The San Bernardino kangaroo rat (Dipodomys merriami parvus) is a species of rodent in the family Heteromyidae. It is one of 19 recognized subspecies of Merriam's kangaroo rat (Dipodomys merriami) that are spread throughout the arid regions of the southwestern United States and Mexico. Like Dipodomys merriami, the San Bernardino kangaroo rat has the diagnostic trait of having four toes on its hind legs. Additionally, because of its geographic isolation, it has become the most highly differentiated subspecies of D. merriami.