Regional odontodysplasia (RO) is an uncommon developmental anomaly affecting a localized area of dentition, with distinctive clinical, radiographic, and histological fi ndings. It is presumed to be the result of a developmental disturbance that locally affects the odontogenic ectodermal and mesodermal tissues. In general, it is limited to only one arch and sometimes it can occasionally cross the midline. Supernumerary teeth (ST) are mammalian developmental abnormalities characterized by the presence of extra teeth in addition to the normal eruption series. Here, we report a case of RO that affected right maxillary teeth crossing the midline and showed two maxillary bilateral impacted ST.