Henri Joannes Maria Claessen (born 1930, Wormerveer) is a cultural anthropologist specialized in the early state and Professor Emeritus in Social Anthropology at Leiden University, He is an honorary member of several scholarly institutions (Koninklijk Instituut voor Taal-, Land- en Volkenkunde [Royal Institute for Languages and Anthropology of the Royal Academy of Sciences]); Center for Asian and Pacific Studies (University of Nijmegen); Honorary Lifetime Member of the IUAES (International Union of Anthropological and Ethnological Sciences).