Andreas Ernestus Josephus Claes (24 October 1885 in Zichem – 2 September 1968 in Elsene) was a Flemish author. He is best known for his regional novels, including "De Witte" ("The White One"), which was the source material for the first Flemish movie: De Witte (1934). 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).
Some of his works are written under the pseudonym G. van Hasselt.
He married the Dutch-born writer Stephanie Vetter.