Aloe andersonii, a new species endemic to Mount Anderson (Map 1), near Lydenburg in the Mpumalanga Province, South Africa, is described (Figures 1–6). It belongs to section Leptoaloe A.Berger, a group of small grass aloes with which it shares an Afromontane habitat (Reynolds 1950). The new species is related to Aloe challisii Van Jaarsv. from which it is distinguished by its short stems of 50–100mm length, firm green leaves which are not subterete, much larger sterile and flowering bracts as well as its cylindric perianth of 30mm in length (Table 2>). The new species was first brought to the attention of the author by Mr Philip Nel.