Introduction: Mandibular third molars are the most frequently affected by impaction. No previous study had been conducted in the Jazan region. Aim of the study: To evaluate the prevalence and patterns of third molar impaction among the Jazanian subpopulation in the southwestern region of Saudi Arabia. Materials and methods: A retrospective study was conducted involving the analysis of the orthopantomograms (OPG) of 1012 patients who attended the Jazan University College of Dentistry. The OPGs were selected randomly from patient records to examine the frequency and pattern of third molar impaction. Data were analyzed, and p < 0.005 was set as significant. Results: A total of 1012 subjects were included, among whom 550 (54.3%) were males. The largest age group was 18-32 years old and accounted for 533 (52.67%) of the subjects. The number of subjects with impacted tooth/teeth was 668 (66%), and frequencies and percentages among the right and left sides did not considerably differ. The number of impacted third molars in mandibular arches was higher than that in maxillary arches. Impactions in Position C were usually in the maxillary arch (116, 11.47%), whereas those in Position A were common in the mandible. Vertical and mesioangular impacted angulations were frequent in the mandibular arch (162, 22.0% and 118, 11.7%). Cases of distolingual impaction were high in the maxillary arch (96, 9.6%). Class II impacted teeth in relation to the ramus were the highest in the right (259, 25.6%), and left (239, 23.62%), followed by Class I impactions. Conclusion: The prevalence of impacted third molars was slightly higher in the Jazan region than in other regions in Saudi Arabia.