Abstract: Grade 3 neuroendocrine tumors (G3 NET) are a rare tumor subtype recently defined by WHO. They are distinct from poorly differentiated neuroendocrine carcinomas (NEC) in histopathological features, therapeutic approach, and prognosis. Due to their low incidence and the scarcity of related studies, standardized diagnostic and treatment guidelines remain incomplete. This review summarizes current evidence on rectal G3 NETs, including clinicopathological characteristics, imaging assessment methods, and major therapeutic approaches, with particular focus on management strategies for both localized and advanced disease. The aim is to provide a reference and to promote the refinement and optimization of management approaches for this uncommon tumor type.