Meningiomas are rare in children. Chordoid meningioma is a very rare variant, as only 16 cases in children have been reported. The authors report the first case of a chordoid meningioma in the third ventricle. A 12-year-old boy presented with headache, abnormal behaviors, and ataxia. Brain MR imaging revealed a 2-cm, well-enhanced mass in the third ventricle and hydrocephalus. Positron emission tomography with [18F]fluorodeoxyglucose showed that the mass was hypermetabolic. Gross-total removal of the mass was performed using a left frontal transcortical and transventricular approach. The mass originated from the left caudate head and was connected to the choroid plexus. A chordoid meningioma was diagnosed on the basis of the histological characteristics of the tumor, which was composed of cords and nests of eosinophilic vacuolated cells with an abundant myxoid matrix, similar to the features of a chordoma. A typical focal meningiomatous pattern was observed. The tumor cells were immunoreactive for vimentin and epithelial membrane antigen. The patient's headache and gait disturbance improved after the tumor was removed. The tumor showed no signs of recurrence during 12 months of follow-up.