Oculomotor nerve palsy is an isolated nerve injury that affects the pupillary muscles. Though pupil dysfunction is a hallmark of third nerve palsy, clinically evaluated using a pen torch test provides categorical data with huge interpersonal variability. Therefore, a quantitative analysis of pupil light reflex is warranted for objective assessment of pupil size and reaction for better perception. So, the current case report is aimed to evaluate the pupil dynamics in a patient with oculomotor nerve palsy. A 37-year-old male patient was admitted to the hospital with severe orbital pain and headache in the frontotemporal region with ptosis and diplopia. A mild light reflex was observed on both sides using a pen torch test. The patient was subjected to dynamic pupillometry where bilateral pupil light reflex was recorded after 5 minutes of dark stabilization. All PLR variables in both pupils Reflex Latency and duration of constriction as well as dilation were prolonged, whereas constriction amplitude and constriction velocity, dilation amplitude and dilation velocity were reduced significantly. The pupil diameter is small even after light stimulus. The current case report reveals that the patient has unilateral third nerve palsy with compromised PLR variables evaluated using dynamic pupillometry.