Ginger is a widespread source of herbal medicine and traditional spices. Among its various bioactive components, ginger polysaccharides (GPs) have attracted the attention of researchers worldwide because of their significant bioactivity. Recent studies have demonstrated the antioxidant, antitumour, anti-inflammatory, immunomodulatory, hypoglycaemic, cough suppressant and thrombotic anticoagulant effects of GPs. However, the structure–bioactivity relationship of GPs has yet to be comprehensively investigated. This review aims to explore all the current published studies on GPs. It further examines various aspects, including the extraction and purification methods, structure, bioactivity, application and structure–bioactivity relationship of GPs. Thus, this review intends to provide a reference for future GP-related research and development.