Giant colloid cysts are defined as cysts of more than 3 cm in maximal diameter. Few cases of giant colloid cysts have been reported in the literature. We herein describe a giant colloid cyst. A 15-year-old female presented with headache, blurred vision, and episodic behavioral changes for 3 months. Neurological examination was limited due to agitation and confusion. Fundoscopy was notable for bilateral papilledema. Brain computed tomography revealed a giant third-ventricular lesion, causing obstructive hydrocephalus. The patient underwent urgent ventriculoperitoneal shunt insertion initially and then cyst excision. The histopathological sections of the lesion were compatible with a colloid cyst. Five years following surgical resection, a brain magnetic resonance imaging did not demonstrate any evidence of residual or cyst recurrence. To our knowledge, giant colloid cysts have been rarely reported and pose a management dilemma in the literature. The present article highlights the symptomatology, radiological findings, and outcome of a giant colloid cyst.