<p>Algal polysaccharides are biological macromolecules composed of multiple monosaccharide units, widely utilized in the food industry for their excellent stabilizing, gelling, and emulsifying properties. They are broadly categorized into seaweed (macroalgae) and microalgae polysaccharides. While seaweed-derived polysaccharides are recognized for enhancing the functional properties of food products, microalgae-derived polysaccharides are increasingly employed in dietary supplements and nutraceutical formulations due to their antiviral, anticancer, and antioxidant properties. These properties have recently brought algal polysaccharides into focus within the food and health sectors. Pre-treatment prior to extraction plays a vital role in determining both the yield and efficiency of algal polysaccharide recovery. Although conventional extraction methods often result in low yields, the adoption of advanced and environmentally friendly techniques such as microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), enzyme-assisted extraction (EAE), pressurized liquid extraction (PLE), and subcritical water extraction (SCWE) has markedly enhanced extraction efficiency. Additionally, effective post-extraction processing strategies are essential to ensure the purity and functionality of the final products. Overall, this review emphasizes the wide range of features and applications of algal polysaccharides in food systems, highlighting their nutritional, functional, and sustainable value in the development of next-generation food products.</p>