AimAs the craniofacial morphology has major effects on the occurrence of obstructive sleep apnea (OSA) in Asians, factors contributing to the severity of OSA may differ depending on craniofacial characteristics. This study investigated factors affecting OSA severity in patients according to craniofacial morphological type.MethodsStudy participants comprised 227 men examined following a diagnosis of OSA between May 2017 and October 2021. We examined cephalometric X‐rays and results of polysomnography on presentation, and classified the craniofacial morphological type of the participant as “long face type” (Group L) for facial axis (Fx) angle <86° or as “short face type” (Group S) for Fx angle ≥86°. We conducted stepwise binomial logistic regression analysis with apnea‐hypopnea index (AHI) ≥ 15 events/h or AHI < 15 events/h as the dependent variable and age, body mass index (BMI), and the cephalometric parameters SNA, SNB, Fx, PNS‐P, MPT, MP‐H, SPAS, MAS, and IAS as independent variables.ResultsBMI and PNS‐P in Group S and BMI and MP‐H in Group L were identified as independent predictors of AHI ≥ 15 events/h.ConclusionsFactors affecting severity of OSA differ by craniofacial morphological type, with factors of obesity and hyoid bone position for long face‐type patients and obesity and soft palate length for short face‐type patients. Optimal treatment requires consideration of craniofacial morphology and establishment of treatment policies that take causative factors into account.