Andreas Ernestus Josephus Claes (24 October 1885 in Zichem – 2 September 1968 in Elsene) was a Belgian author. He is best known for his regional novels, including De Witte ("Whitey"), which was the source material for the first Flemish movie: De Witte (1920). In 1980 it 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) or miniseries as De vulgaire geschiedenis van Charelke Dop (1985).
Some of his works are written under the pseudonym G. van Hasselt.
He married the Dutch-born writer Stephanie Vetter.
Naar het kasteel (published in "De Groene Linde") (1905)