Suprascapular neuropathy may occur as a result of traction, direct trauma, repetitive microtraumas, and extrinsic compression. A thirty-one-year-old man presented with non-traumatic complaints of right shoulder pain and stiffness. After exclusion of other causes associated with shoulder pain, a diagnosis of suprascapular nerve entrapment was considered. Electromyographic activity of the right shoulder was compared with that of the left side and involvement of the infraspinatus muscle was detected, with the supraspinatus muscle appearing normal. Magnetic resonance imaging revealed a ganglion cyst around the spinoglenoid notch. The patient underwent arthroscopic examination and open cyst excision. Arthroscopy did not show any labral tears. Pathological diagnosis was made as a cystic ganglion. On follow-up examinations, the patient's complaints disappeared and only minimal infraspinatus muscle atrophy was observed. Suprascapular nerve entrapment should be considered in the differential diagnosis of posterior shoulder pain.