Extracellular polysaccharides (EPS) are the kind of complex carbohydrates secreted by various microorganisms, like bacteria, fungi, and algae. In recent years, EPS have received increasing interest, beyond the already established functional properties they possess toward possible prebiotic applications. Prebiotics are substances that stimulate the growth and activity of beneficial gut microbiota, which help maintain good digestive health. This chapter summarizes the recent studies on health benefits of EPS as prebiotics in modulating gut microbiota and host metabolism. This interaction between EPS and the intestinal microbiota is crucial for microbial ecosystem maintenance because these polysaccharides are used as a substrate by beneficial bacteria (like Bifidobacterium or Lactobacillus). These microorganisms are capable of fermenting EPS resources in the production of short-chain fatty acids (SCFAs), reflecting on the maintenance and homeostasis from intestinal state, decreasing inflammatory mediators and possibly preventing pathogenic bacteria colonization. Studies have shown that EPS-producing probiotics can improve the performance of fermented foods, which may provide new therapeutic uses in gastrointestinal diseases, immune modulation, and metabolic health. This chapter highlights key studies exploring the structure–function relationship of EPS and their influence on microbiome from different microbial sources, including lactic acid bacteria, cyanobacteria (blue-green algae), and yeast. A broad background review of the interplay between EPS, gut microbiota, and fermentation products in association with various health benefits will also be introduced. In addition, it will argue the EPS as next generation prebiotics and emphasize research needs, which are still lacking in gut health for medicinal implication.