A new species of Astroloba, A. tenax Molteno, Van Jaarsv. & Gideon F.Sm., is described from the northern foothills of the Groot Swartberg Mountain, in the Prince Albert area of the Western Cape Province, South Africa. The species is related to the allopatric A. bullulata (Jacq.) Uitewaal, but can easily be distinguished by vegetative and floral characters. Its geographical distribution range overlaps with that of two further entities—A. herrei Uitewaal, and an as yet undescribed species (informally known as ‘Astroloba foliolosa subsp. robusta’, submitted for publication as Astroloba robusta P.Reinecke ex Molteno, Van. Jaarsv. & Gideon F.Sm.)—both of which flower in winter to spring (June to September), while A. tenax flowers in mid-summer (November to January) in the southern hemisphere. As a result of the different flowering times of these taxa, natural hybrids have not been recorded among the populations.