Objectives: The aim of this study was to compare the tooth dimensions of an orthodontic patient population with a normal population of Nigerians. Materials and Methods: Participants were orthodontic and control populations selected from Obafemi Awolowo Teaching Hospitals Complex Ile-Ife. Selected participants had full eruption of first six permanent teeth in all quadrants, intact dentition and no conservative treatment other than class 1 restorations. The mesio-distal and bucco-lingual widths of teeth were measured with an electronic digital caliper from dental casts. Independent sample t test was used for group comparisons. Statistical significance was inferred at p < 0.05.Results: Mean maxillary and mandibular mesio-distal tooth dimensions were generally larger in the orthodontic than the control population, however, only the dimensions of maxillary central incisors, left lateral incisor and mandibular left second premolar differed significantly (p < 0.05). Mean maxillary bucco-lingual tooth dimensions were significantly larger among the orthodontic than the control population. Mandibular bucco-lingual dimensions differed significantly for the right canine, left first and second premolars, and right and left first molars (p < 0.05). Tooth dimensions were generally larger in male than female participants, however only a few differences reached statistical significance (p < 0.05) Conclusions: Some differences were observed in the mesio-distal tooth dimensions of the orthodontic patients and control patients who participated in this study, especially in relation to the maxillary incisors. Buccolingual tooth dimensions differed significantly between the groups which were more pronounced with the maxillary teeth. Gender differences were observed with some tooth dimensions.