Mucilages and gums are natural hydrocolloids with distinctive functional properties and widespread applications in the food and healthcare industries. Recent research has focused on identifying, characterizing, and exploring novel sources of these compounds. Quince seed mucilage (QSM) is one such inexpensive and biocompatible option, offering various functional properties and applications across food and non-food sectors. The QSM structure comprises cellulosic and non-cellulosic fractions. The non-cellulosic fraction is primarily composed of glucuronoxylans, which are rich in glucuronic acid residues. Due to its unique chemical composition and molecular structure, QSM exhibits pseudoplastic behavior and can modify texture as a thickener and hydrogel former. It has the potential to stabilize emulsions and foams, form films and scaffolds, and deliver active materials. Moreover, QSM could serve as a smart biomaterial in diverse biomedical applications. This review summarizes current knowledge on QSM, focusing on its extraction, chemical composition, and techno-functional properties. QSM’s potential applications in food, pharmaceuticals, and biomedical fields are highlighted. This review aims to provide a comprehensive resource for researchers and industries seeking to utilize QSM for enhanced product development.