Moebius syndrome (MS) is a rare disorder mainly characterized by bi- or unilateral palsy of the facial and abducens nerves. Among the various orofacial characteristics related to this syndrome, the following are pointed out, difficulty with sucking, tongue malformation, mandibular hypoplasia, saliva drooling, arched palate and micrognathia. In spite of the diversity of oral features described for these patients, self-inflicted oral trauma has not yet been reported. Therefore, the purposes of the present report were to describe an unusual case of a baby with Moebius syndrome who had a parafunctional habit that resulted in a persistent traumatic lesion of the lower lip, and discuss the treatment performed.