Suprascapular nerve dysfunction caused by ganglion cysts is a rare condition that can cause significant pain and weakness in the shoulder. The suprascapular nerve is a branch of the brachial plexus that innervates the supraspinatus and infraspinatus muscles. It is most commonly compressed at the suprascapular notch or the spinoglenoid notch. A 40-year-old male presented with a two-year history of left shoulder pain that was aggravated by overhead activities. Physical examination revealed mild tenderness along the infraspinatus with noticeable atrophy, full range of motion, and mild external rotation weakness. MRI was obtained and confirmed the suspected diagnosis of suprascapular nerve dysfunction caused by a ganglion cyst at the spinoglenoid notch. The patient was initially treated conservatively with physical therapy and non-steroidal anti-inflammatory drugs (NSAIDs), but after completing nine months of conservative management, he showed no improvement. The patient elected to undergo open ganglion cyst excision and decompression of the spinoglenoid notch. Postoperatively, the patient's pain resolved gradually and he regained the full power of external rotation. The patient was followed for one year postoperatively and was satisfied with the outcome with a full range of motion, full power, and a complete return to his baseline level of activity. In conclusion, this case report demonstrates the successful treatment of suprascapular nerve dysfunction caused by a ganglion cyst at the spinoglenoid notch with open ganglion cyst excision and decompression. This procedure is a safe and effective treatment option for patients with this condition who have failed to respond to conservative treatment and emphasizes and signifies the role of eliciting a detailed patient history, conducting a thorough radiographic examination including MRI scans, and planning optimum surgical interventions