Purpose Measurement of optic nerve sheath diameter (ONSD) with ocular ultrasonography (USG) is a noninvasive technique that can be readily used to determine clues of increased intracranial pressure. In this study, we aimed to determine the role of optic nerve sheath diameter measurements in the diagnosis and follow-up of pediatric patients with idiopathic intracranial hypertension (IIH). Methods Eight patients with a diagnosis of IIH with a median age of 11.7 (range 4.5-17) years were examined prospectively. During follow-up, orbital ultrasonography (USG) was performed immediately prior to lumbar puncture (LP) and at 24 h, at 1 week, and between 1 and 18 months after LP. Cranial MRI examinations and automated visual field assessments were performed at baseline and at 3 months, and both measurements were compared with each other. Results The mean cerebrospinal fluid opening pressure (37.75 +/- 12.64 cm H2O) and the mean ONSD (5.94 +/- 0.46 mm) were correlated. The median follow-up was 16 (range, 12-18 months), and ONSD regressed gradually consistent with clinical and radiologic improvement during follow-up. Conclusions To the best of our knowledge, this is the first prospective pilot study performed on pediatric patients with IIH using orbital USG for ONSD measurements. Despite the small sample size, the present study indicated that orbital USG may be used as a promising noninvasive tool to diagnose increased intracranial pressure and for monitoring treatment efficacy in this special patient population.