Xanthesma nigrior, or Xanthesma (Xanthesma) nigrior, is a species of bee in the family Colletidae and the subfamily Euryglossinae. It is endemic to Australia. It was described in 1965 by American entomologist Charles Duncan Michener.
The species occurs in the Wheatbelt region of Western Australia. The type locality is between Karalee and Dedan. Other published records include Yellowdine and Merredin.
The adults are flying mellivores.