Intracranial teratomas are rare tumors that usually present during the second decade of life. Among intracranial teratomas, suprasellar germ cell tumors in particular are extremely rare. We present the case of an 18-year-old girl who underwent a successful endoscopic transnasal resection of a suprasellar teratoma with a mixed germ cell component. An 18-year-old girl presented with progressive visual disturbance, headache, weight loss, and fatigue for 2 weeks. She had decreased vision in her right eye and double vision when looking to the right side. On examination, she had right-side complete abducens nerve palsy and partial oculomotor nerve palsy bilaterally. Brain imaging revealed a large suprasellar lesion consistent with a germ cell tumor. The patient underwent a transnasal endoscopic resection of the lesion. Pathology showed a mixed germ cell tumor (80% mature cystic teratoma, 18% yolk sac tumor, and 2% germinoma). The mature teratomatous elements identified included skin with sebaceous material, hair, cartilage, acini, colonic mucosa, muscle, nerve bundles, and adipose tissue. Postoperative magnetic resonance imaging (MRI) showed residual tumor in the left cavernous sinus and anterior clinoid process superiorly. At a 1-year follow-up, the double vision had resolved, and her vision showed progressive improvement. The patient was maintained on treatment for diabetes insipidus, hypothyroidism, and adrenal insufficiency. Her last MRI showed no signs of tumor progression. The present case demonstrates a safe endoscopic transnasal surgical resection of a rare suprasellar tumor, mixed teratoma, with intra-axial extension. The endoscopic transnasal approach can be considered a valid option for a suprasellar lesion.