Department of Oncology, First People’s Hospital of Jingzhou, Jingzhou, China Objective: This study aimed to compare dosimetric differences and normal tissue complication probability (NTCP) among coplanar intensity-modulated radiation therapy (CO-IMRT), non-coplanar IMRT (NONCO-IMRT), coplanar volumetric-modulated arc therapy (CO-VMAT), and non-coplanar VMAT (NONCO-VMAT) in thymoma radiotherapy and clarify the value of non-coplanar plans.