Necrotizing fasciitis is a soft tissue infection that habitually originates from the fascial sheaths, expands at a volant pace, leads to extensive necrosis of the subcutaneous tissues, and eventually ends up in a life-threatening condition with notably elevated amputation and mortality rates. Factors that induce interruption of skin integrity, such as trauma or intravenous drug use, are the most common inciting events. Specific clinical signs heralding its presence are usually absent in the early stages, often resulting in misdiagnosis. Early recognition, prompt and aggressive surgical debridement, antibiotic use, and supportive care constitute the fundamental principles to lean on for a better prognosis. Necrotizing fasciitis of the upper extremity is relatively rare and consequently holds a limited place in the literature. Only a few studies assess it as a separate entity, with most of them being case reports or small case series. We, therefore, performed a review of the current literature, to assemble the dispersed results of different studies and clarify the various aspects of upper limb necrotizing fasciitis. In this systematic review, we present the epidemiological data, the causative events, the most frequent underlying diseases, the risk factors, the amputation and mortality rates, the pathogenic microorganisms, the clinical characteristics, the diagnostic tools, the medical and surgical management concerning necrotizing fasciitis of the upper limb. Finally, the results indicating its differentiation compared to necrotizing fasciitis of other anatomic sites are remarkably highlighted.