Pritchardia aylmer-robinsonii is a species of palm tree that is endemic to the island of Niihau, Hawaii, United States. It inhabits coastal dry forests at an elevation of . P. aylmer-robinsonii reaches a height of and a trunk diameter of . Harold St. John discovered this species in 1949, and the specific epithet refers to Aylmer Francis Robinson, a member of the family that owned the island. P. aylmer-robinsonii has been reintroduced to the Makauwahi Cave Reserve on Kauai, where the species is believed to have previously ranged.