<p>This report presents a unique case of a 15-year-old girl who exhibited an acute atypical catatonic presentation associated with obstructive hydrocephalus and was successfully managed with endoscopic third ventriculostomy (ETV). The patient, with no significant past medical, family, or developmental history, initially experienced headaches followed by a rapid decline in responsiveness and verbal communication over the subsequent days, leading to urgent medical attention. Neuroimaging revealed obstructive hydrocephalus with impaired cerebrospinal fluid (CSF) flow through the cerebral aqueduct. She underwent an urgent ETV, and postoperatively, she showed a rapid improvement, with resolution of the catatonic symptoms. This case highlights the importance of early neuroimaging in children presenting with neuropsychiatric symptoms, as this may be caused by a reversible underlying surgical disease such as hydrocephalus. To the best of our knowledge, this is also the first case in the literature of a child treated successfully with ETV for obstructive hydrocephalus presenting with catatonic symptoms.</p>