The digestive system of the beira (Dorcatragus megalotis), a small East African antelope, has not been described previously. We present anatomical data collected from the only known captive population of the species, allowing for a first understanding of the morphophysiological ‘type’ of this species. The gastrointestinal anatomy was quantified by weights, dimensions and areas, measured in a total of 19 beiras (ranging in body mass from 3.5 to 13.5 kg; not all measures taken in all animals). These characteristics were then evaluated against a comparative dataset consisting of data from both browsing and grazing ruminants. Overall, for example, in terms of reticular crest height, masseter mass and omasal laminar surface area, the beira digestive tract resembled that of the browsing ‘moose-type’ ruminants. A diet of dicotyledonous plant material was further supported by the carbon isotope composition (δ13C = -27.5‰) typical for C3 plants of a faecal sample collected from a wild specimen, as well as the limited ecological information available for the species.