Hexactinellida, commonly referred to as glass sponges, are predominantly found in deep marine environments, typically at depths ranging from 200 to 6,000 metres. Until now, the Hexactinellida fauna of South Africa has been largely unexplored, with only 1.8% of the known extant hexactinellid species accounted for. This study described one new family, one new genus, and eight new species of Hexactinellida from various deep-water environments in South Africa, using both morphological and genetic data. The newly erected family, Cyrtaulonidae fam. nov., accommodates the genus Cyrtaulon together with the newly established genus Amatholon gen. nov. The species described include Pheronema colossum sp. nov., Hyalonema (Cyliconema) hagahagaense sp. nov., Hyalonema (Cyliconema) thukelaense sp. nov., Sclerothamnus mbuyazii sp. nov., Hexactinella agulhasensis sp. nov., Hexactinella amatholensis sp. nov., Amatholon amatholicum gen. et sp. nov. and Regadrella tamsynae sp. nov. Additionally, we describe Acanthascus (Rhabdocalyptus) baculifer from fresh material, and our research documents the presence of the family Aphrocallistidae in South Africa for the first time. These findings contribute to the understanding of hexactinellid diversity and underscore the necessity for further investigation into the deep oceans of South Africa.