Three chameleons have been described from southern Arabia: Chamaeleo calyptratus Duméril & Duméril, 1851; Chamaeleo calcarifer Peters, 1871 and Chamaeleo arabicus (Matschie, 1893). Chamaeleo arabicus is clearly connected with typical Chamaeleo chamaeleon by intermediate forms: Chamaeleo chamaeleon orientalis Parker, 1938 and Chamaeleo chamaeteon musae Steindachner, 1900 and it thus may be regarded a subspecies of Chamaeleo chamaeleon itself. Chamaeleo calyptratus, though in many respects clearly related to the group around Ch. chamaeleon, shows so many differences, whereas the range lies in the midst of the range of Ch. chamaeleon arabicus, that it is considered here as a true species. Chamaeleo calcarifer possesses a mixture of characters of Ch. chamaeleon arabicus and Ch. calyptratus, whereas no single character may be mentioned that is typical for this form only. Probably it is to be considered a hybrid of these two species, though the provenance is unknown.