The Nannowithius group of the pseudoscorpion family Withiidae is newly defined, consisting of Nannowithius Beier, 1932 from northern Africa and the Middle East, and Termitowithius Muchmore, 1990 from east Africa. The group is characterized by the lack of a tactile seta on the posterior tarsi, and they are the only withiids to possess this character state. Both genera are associated as inquilines with social insects, Nannowithius with ants and Termitowithius with termites. Withius caecus Beier, 1929 and Plesiowithius dekeyseri Vachon, 1954 are redescribed and transferred to the genus Nannowithius, forming the new combinations N. caecus (Beier) and N. dekeyseri (Vachon). Plesiowithius is treated as a new synonym of Nannowithius. A revised description and new illustrations of Termitowithius kistneri Muchmore, 1990 are presented.