Intraosseous ganglion cysts (IGC) of the carpal bones are frequently reported in the literature, involving at most two carpal bones of the same wrist. Only one case recently described the presence of multiple intraosseous ganglion lesions in the capitate, lunate, and triquetrum, resulting in chronic wrist pain. The following study reports the first case of multiple IGCs causing a unilateral carpal tunnel syndrome (CTS), in a 56-year-old woman, with no previous history of trauma. Failure of conservative management prompted carpal tunnel release and the surgical excision of the ICGs, followed by autologous bone grafting to fill in the defects. Consequently, IGCs must be considered in the differential diagnosis of unilateral CTS due to the expansile nature of the bone lesions.