Thomas Sylvester Barthel (4 January 1923 in Berlin – 3 April 1997 in Tübingen) was a German ethnologist and epigrapher who is best known for cataloguing the undeciphered rongorongo script of Easter Island. In 1959 Barthel became Associate Professor of Ethnology at the University of Tübingen, and from 1964-1988 he was Professor of Ethnology. His primary research was in the folklore of the Americas. He bequeathed his rongorongo data to the CEIPP (Centre d'Études de l'Îles de Pâques et de la Polynésie), which is engaged in verifying and expanding on his work.