Scaphocephaly, also called sagittal synostosis, is the most common form of craniosynostosis characterized by premature fusion of the sagittal suture. Tentorium cerebelli hypoplasia, a rare developmental anomaly, involves underdevelopment of the structure that separates the supratentorial and infratentorial spaces of the brain. Although both diseases have been reported individually, their simultaneous occurrence has not been documented in the literature. A 37-year-old female patient presented to the traumatology department after a minor car accident. A CT scan of the head and neck revealed no traumatic injuries but incidentally discovered scaphocephaly and bilateral tentorium cerebelli hypoplasia. The rostral portion of the tentorium cerebelli was absent on both sides, with the cuneus protruding into the quadrigeminal cistern on both sides, more visible on the right side. The patient did not exhibit any neurological deficits or symptoms typically associated with these disorders. Scaphocephaly is known to result from premature closure of cranial sutures, often leading to increased intracranial pressure, developmental delays, and cognitive impairment. Although rare, tentorium cerebelli hypoplasia is associated with symptoms such as headaches, dizziness, and seizures. The co-occurrence of these disorders may indicate a common developmental pathway, although further research is needed to confirm this. This case represents a unique combination of scaphocephaly and bilateral tentorium cerebelli hypoplasia revealed incidentally in an asymptomatic patient. It highlights the potential for variability in clinical presentation and the importance of imaging in identifying such developmental anomalies. Further studies are needed to investigate the relationship and clinical significance of these two diseases.  Kulcsszavak: craniosynostoses, scaphocephaly, sagittal synostosis, dura mater, tentorium cerebelli