Ulnar tunnel syndrome results from compression of the ulnar nerve at the wrist. It occurs much less commonly than ulnar nerve compression at higher levels, but should be considered in the differential diagnosis for any patient presenting with signs and symptoms of ulnar neuropathy. The space through which the ulnar nerve passes in the wrist was first broadly described by the French urologist and surgeon Jean Casimir Felix Guyon in 1861 [1, 2], and our understanding of the anatomy and borders of this complex region has subsequently evolved. Unlike carpal tunnel syndrome which is commonly idiopathic, ulnar tunnel syndrome is often secondary to mass effect from another process like ganglion cyst, ulnar artery thrombosis, fracture, anomalous anatomy and etc. For this reason CT or MRI imaging, in addition to plain wrist radiographs and electrodiagnostic studies, is often indicated in the workup. Surgical management addresses the underlying cause of compression. This chapter reviews the clinical presentation of ulnar tunnel syndrome, the relevant patho-anatomy, workup, and longitudinal management.