A synopsis of the phylogeny and systematics of subfamily Betoideae of the Chenopodiaceae is provided and a modified subfamilial classification proposed. Betoideae contain five or six genera, i.e. Beta, Patellifolia, Aphanisma, Oreobliton and Hablitzia. The inclusion of Acroglochin in Betoideae is not clearly resolved by molecular evidence. The five genera (excl. Acroglochin) fall into two clades. These are Beteae with Beta only, and Hablitzieae with the remaining four genera. Of these four genera, Patellifolia formerly has been regarded as a section of Beta (B. sect. Procumbentes). The closer relationship of Patellifolia to Hablitzieae rather than to Beta is supported not only by molecular but also by flower morphological characters. Molecular evidence, in part newly generated, suggests that Beta can be divided into two well-supported groups. These are B. sect. Corollinae and B. sect. Beta. The often recognized unispecific B. sect. Nanae should be included in B. sect. Corollinae. In B. sect. Beta, probably only two species, B. macrocarpa and B. vulgaris, should be recognized.