Protein–polysaccharide interactions are key to determine the techno-functional and nutritional properties of food systems. Proteins and polysaccharides can form complexes that strongly affect the digestion mechanism by different pathways. Polysaccharides may reduce protein digestibility by altering protein conformation, increasing the viscosity of the digestive medium, inhibiting digestive enzymes, and/or promoting or hindering interactions with physiological components, such as bile salts and phospholipids. This is expected to affect the intestinal transport process and bioavailability of nutrients. Thus, understanding the mechanism and impact of protein–polysaccharide interactions is crucial for designing efficient processing strategies and predicting the nutritional impact of foods.