Galactomannans are a class of hemicellulose polysaccharides found in the seeds of various plant species. They help protect embryos and facilitate germination. Because they are water‑soluble and exhibit distinctive rheological behaviour, galactomannans are widely used as thickeners, emulsifiers, and stabilizers across multiple industries as an eco‑friendly and biodegradable alternative to synthetic polymers. In the food sector, they are added to enhance texture, sensory attributes, and shelf life of dairy products, beverages, baked goods, fruits and vegetables. Their non‑toxicity, biocompatibility, and antimicrobial properties also make them suitable for pharmaceutical applications such as drug delivery systems, tablet binders, and tissue engineering. The cosmetic, textile, and paper industries likewise exploit galactomannans for their hydrating, moisturizing, and conditioning effects; coagulating ability; and favourable mechanical properties, respectively. However, challenges in efficient extraction and purification, structural variability depending on the plant source, and the relatively weak mechanical properties of native galactomannans limit their broader industrial adoption. Recent research, therefore, emphasizes functionalization or reinforcement of galactomannans with other polymers or bioactive molecules to mitigate these drawbacks. This chapter aims to review the fundamental structure and properties of galactomannans, summarize their industrial applications, and outline future prospects and considerations for their wider commercial use.