Harald Tandrup (31 January 1874 in Copenhagen – 10 May 1964) was a Danish writer. He used the pseudonyms Claus Colding or Klavs Kolding. His first novel was entitled Ain-Mokra and appeared 1900. He also wrote Reluctant Prophet (first U.S. edition in 1939). In 1946 he was excluded from the Danish Writer's Association (Danske Dramatikeres Forbund).