Manius Acilius Glabrio
Faustus was the son of Acilius Glabrio Sibidius, who is known from a dedication to him from Faustus. Sibidius was a member of the lineage of the Acilii Glabriones, who descended from the consul of 191 BC, Manius Acilius Glabrio. Cameron states his mother was one of the house of the gens Anicia, although unable to identify the woman. His descendants include Rufius Achilius Maecius Placidus (cos. 481), Anicius Acilius Aginantius Faustus (cos. 483), and Rufius Achilius Sividius (cos. 488).