This review discusses the potential of polymeric nanoparticles (PNPs) for oral insulin delivery, addressing the challenges and advancements in this field. Oral insulin administration is hindered by gastrointestinal enzymes, pH variations, mucus, and mucosal layers, leading to low bioavailability. PNPs, particularly natural and synthetic porous polymers, offer promising solutions by improving insulin loading capacity, stability, and bioavailability while reducing side effects. The review covers controlled release mechanisms, recent applications of PNPs in oral insulin delivery, and future prospects. Key strategies include pH-responsive and glucose-responsive systems, which enhance insulin stability and release in the gastrointestinal tract. Natural polymers like chitosan, starch, and dextran, and synthetic porous polymers like metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) are highlighted for their unique properties and potential in oral insulin delivery. Despite progress, long-term efficacy and safety in larger animals and humans need further validation. The review concludes by emphasizing the need for optimized encapsulation efficiency, loading capacity, gastrointestinal stability, bioavailability, and intestinal permeation ability before clinical trials can be initiated.This review discusses the potential of polymeric nanoparticles (PNPs) for oral insulin delivery, addressing the challenges and advancements in this field. Oral insulin administration is hindered by gastrointestinal enzymes, pH variations, mucus, and mucosal layers, leading to low bioavailability. PNPs, particularly natural and synthetic porous polymers, offer promising solutions by improving insulin loading capacity, stability, and bioavailability while reducing side effects. The review covers controlled release mechanisms, recent applications of PNPs in oral insulin delivery, and future prospects. Key strategies include pH-responsive and glucose-responsive systems, which enhance insulin stability and release in the gastrointestinal tract. Natural polymers like chitosan, starch, and dextran, and synthetic porous polymers like metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) are highlighted for their unique properties and potential in oral insulin delivery. Despite progress, long-term efficacy and safety in larger animals and humans need further validation. The review concludes by emphasizing the need for optimized encapsulation efficiency, loading capacity, gastrointestinal stability, bioavailability, and intestinal permeation ability before clinical trials can be initiated.