Objective: To evaluate the prevalence of periodontal biotypes in patients with skeletal Class III malocclusion and to explore its association with age, gender, other periodontal clinical parameters and width of keratinized gingiva (WKG). Methods: Data were collected for the buccal-middle site of 310 anterior teeth from 26 subjects who received periodontally accelerated osteogenic orthodontics (PAOO) surgery before orthodontic treatment. Univariate and multivariate analysis were performed to calculate and test the correlations between periodontal biotype and age, gender and bleeding index (BI), gingival recession (GR), plaque index (PLI), probing depth (PD) and WKG. Results: Prevalence of thin periodontal biotype was 33.9% in the anterior region. Mean WKG was 4.37 mm. Univariate analysis showed that a moderately positive correlation was found between WKG and thick biotype (r = 0.544, P 0.001). A low positive correlation was detected between mandibular teeth and thick biotype (r = 0.387, P 0.001) and a low negative correlation was detected between GR and thick biotype (r = -0.308, P 0.001). Multi-level logistic regression showed that biotype was significantly associated with dental arch (odds ratio [OR] = 0.174, P = 0.015) and WKG (OR = 2.043, P = 0.002). No significant associations were detected between biotype and other factors. Conclusion: Dental arch and WKG were associated with periodontal biotype in patients with skeletal Class III malocclusion. Keywords: periodontal biotype, keratinized gingiva, skeletal Class III malocclusion, orthodontic treatment