Andricus is a genus of oak gall wasps in the family Cynipidae.

As in all Hymenoptera, sex-determination in species of the genus Andricus is governed by haplodiploidy: males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid.

[2] Many species in the genus alternate between an asexual generation and a sexual generation.

[3][4] The taxonomy of the genus Andricus is uncertain, with many of the approximately 375 species considered dubious.

[5] The following species are currently recognised in the genus Andricus:[6][7][8][9] These species were previously grouped in Andricus.