Joubert syndrome is a rare neurodevelopmental disorder characterized by cerebellar vermis hypoplasia and a broad clinical and genetic spectrum. Some KIF7-related Joubert syndrome cases show overlapping acrocallosal features, including additional central nervous system malformations and hydrocephalus requiring neurosurgical intervention. Although ventriculoperitoneal shunting is commonly used in pediatric hydrocephalus, intrathoracic complications are rare. We report a term-born male patient with KIF7-related Joubert syndrome with acrocallosal features who developed pleural effusion 20 months after ventriculoperitoneal shunt placement. Thoracic ultrasonography demonstrated bilateral pleural effusion. β2-transferrin analysis confirmed the presence of cerebrospinal fluid (CSF) in the pleural fluid. Imaging studies revealed an intact shunt system without intrathoracic migration or mechanical failure. Exploratory laparoscopy identified no macroscopic diaphragmatic defect, and the overall clinical course supported presumed impairment of peritoneal CSF absorption with secondary pleural accumulation. CSF-related pleural effusion should be considered in VP-shunted children presenting with respiratory symptoms even in the absence of catheter migration. After alternative causes have been excluded, impaired peritoneal absorption with transdiaphragmatic CSF passage may be considered a plausible but unproven mechanism.