Sagittal synostosis is a common non-syndromic synostosis treated with open or endoscopic cranial vault remodeling. Early intervention is recommended to avoid restricted brain growth, increased intracranial pressure, and resultant developmental delay. Common complications such as failure or reconstruction, cerebrospinal fluid leak, blood loss, and stroke are well-reported in the literature. Here, we present a rare case of the development of a subdural hygroma following cranial vault remodeling in a seven-month-old male, necessitating the insertion of a subdural-peritoneal shunt.