Gundis (Ctenodactylus gundi) are gregarious, rock-dwelling rodents found in northern Africa. Very little is known about the behavioral ecology of C. gundi, or any other ctenodactylid rodent. The current study uses mark and recapture data of social groups of C. gundi in Tunisia to ascertain information on group composition and to obtain preliminary evidence on group formation. The majority of groups were found to be multimale and multifemale. Group size averaged 5.6 individuals ± 2.0 SD with 2.6 ± 0.9 adult males and 3.0 ± 1.7 adult females per social unit. Examination of recapture data suggests that groups of C. gundi result from both male and female natal philopatry in conjunction with male-biased dispersal. This study provides evidence that C. gundi may be a cooperatively breeding rodent, although results may be confounded by the effect of a drought.