Andreas Ernestus Josephus Claes (24 October 1885 in Zichem – 2 September 1968 in Elsene) was a Belgian writer. He is most famous for his regional novels, such as De Witte ("Whitey"), which served as the basis for the first Flemish sound film: De Witte (1920). In 1980, the story was remade as De Witte van Sichem by Robbe De Hert.
Claes’ novels were also adapted into the popular TV series Wij, Heren van Zichem (1969–1972) and the miniseries De vulgaire geschiedenis van Charelke Dop (1985).
Some of his works were written under the pseudonym G. van Hasselt.
He married the Dutch-born writer Stephanie Vetter.