The global seafood industry generates significant biomass waste, a large portion of which comprises the squid gladius (pen). Historically discarded, this structure is now recognized as a valuable source of ?-chitin, a biopolymer distinct from the ?-chitin found in crustaceans. This article reviews the valorization of squid pens into ? -chitosan, highlighting its unique parallel chain structure which facilitates milder, eco-friendly extraction processes and superior solubility. The review further examines the physicochemical advantages of ?- chitosan, including enhanced water-binding capacity and reactivity. Finally, it explores the material's versatile applications ranging from antimicrobial food packaging to biomedical hydrogels, emphasizing its superior biosecurity and hypoallergenic profile compared to crustacean-derived alternatives.