Aim: Evaluate the relationship between maxillary transverse dimensions and impacted maxillary canines using cone beam computed tomography (CBCT). Materials and Methods: This retrospective radiographic study reviewed 45 CBCT records of 45 subjects their ages above 12 years. The records were divided into 3 groups, Group I: normally erupted maxillary canine group (control group), group II: labial impacted maxillary canine group, group III: palatal impacted maxillary canine group. Maxillary width was measured at 4 levels: basal first molar width, alveolar first molar width, basal first premolar width, and alveolar first premolar width. The depth of the palatal vault was measured to evaluate the shape of the palate in all groups. Results: labial and palatal impacted groups showed significantly smaller basal first molar widths, alveolar first molar and first premolar widths, compared with the control group (P < 0.05). Basal first premolar widths and palatal vault depths were not significantly different between the groups. Conclusions: Maxillary width was smaller in subjects with labial or palatal maxillary canine impaction than subjects without impaction.