Objective <p>To determine the frequency and types of cysts and tumors around the impacted mandibular third molars (IMTMs) in the Thai population.</p> Methods <p>This study was a retrospective study of the histopathologic results of the lesions associated with IMTMs from January 2022 to December 2023. In addition, the age and sex of the patients, panoramic radiographs were also reviewed. The IMTMs with other impacted teeth and patient who had incomplete data record or poor quality panoramic films were excluded.</p> Results <p>In a period of two years, the 2,355 IMTMs were removed. Among these, the incidence of cysts and tumors around IMTMs was 1.86% (44 lesions of 42 patients). The mean age was 36.07&#xa0;years with male predominance. Most cases (72.73%) demonstrated unilocular radiolucency in the radiographs. The incidence of cysts around IMTMs was 1.57% with dentigerous cysts in majority. Bilateral dentigerous cysts associated with IMTMs were found in 2 patients with no underlying syndromes or systemic diseases. While the incidence of benign tumors around IMTMs was 0.29% with ameloblastoma in majority, malignancy was not found.</p> Conclusion <p>Although the results indicated that cysts and tumors can develop in relatively small chances in a minority of patients, it was a crucial pathologic condition that cannot be underestimated due to complications after surgery. The decision to remove IMTMs requires careful thought and evaluation for individual patients.</p>