Thymoma is the most common tumor in the anterior mediastinum (50% in adults). This review presents an update of thymoma treatment, commonly based on the Masaoka clinical staging system. The best treatment option is complete resection with no adjuvant approach in early stages and complete response. For incomplete resection, postoperative radiotherapy is recommended (5-year survival: 50-60%). For unresectable disease, concurrent chemoradiotherapy is performed. In conclusion, high technology (3D radiotherapy, 4D radiotherapy, intensity-modulated radiotherapy, image-guided radiotherapy and computed tomography fusion with PET scan) optimizes tumor target definition and provides dose escalation.