Acastidae is a family of trilobites in the order Phacopida, suborder Phacopina, superfamily Acastoidea, containing the following genera:

Acastava Acaste Acastella Acastellina Acastocephala Acastoides Acastopyge Armorigreenops Asteropyge Baniaspis Bellacartwrightia Bradocryphaeus Braunops Breizhops Centauropyge Chimaerastella Coltraneia Comura Cryphina Delocare Deloops Destombesina DunopygeEchinopyge Erbenochile Ewacaste Feruminops Gourdonia Greenops Gudralisium Hallandclarkeops Harringtonacaste Heliopyge Hexacosta Hollardops Kayserops Kennacryphaeus Kloucekia Llandovacaste Metacanthina Mimocryphaeus Minicryphaeus Morocconites Mrakibina Neocalmonia NeometacanthusParacryphaeus Pelitlina Phacopidina Philonyx Pilletina Protacanthina Pseudocryphaeus Psychopyge Quadratispina Quadrops Radiopyge Rheicops Rhenops Saharops Sanidopyge Scotiella Sokhretia Stummiana Talus Tolkienia Treveropyge Turcopyge Walliserops