Longitudinal growth changes in the transverse and vertical craniofacial dimensions occurring between 10 and 14 years of age were evaluated in 22 female and 23 male subjects. All subjects were healthy, had a clinically acceptable occlusion, and had not received orthodontic or orthopedic therapy before. Serial cephalometric radiographs were taken at ages 10, 11, 12, and 14 years. In studying the P-A cephalograms, seven transverse and five vertical measurements were used. The effects of age and sex on the transverse and vertical growth of the craniofacial structures were investigated by means of analysis of variance and Bonferroni multiple comparison test. The results of the study revealed that all measurements studied were affected by age, and cranial, facial, nasal, and maxillary widths were affected by sex. The most pronounced age-related increases occurred in the mandibular width for transverse measurements and in the total facial height for vertical measurements in both sexes during this study.