Polymeric nanoparticles (PNPs) are promising for oral insulin delivery due to their ability to enhance bioavailability and overcome challenges like gastrointestinal enzymes and pH variations. This review summarizes recent advancements in PNPs for oral insulin delivery, focusing on controlled release mechanisms, challenges, and future prospects. PNPs offer advantages such as stability, biocompatibility, and controlled drug release. They can protect insulin from degradation in the gastrointestinal tract and facilitate its delivery to the liver via the portal vein. PNPs are classified into natural polymers (e.g., chitosan, dextran, starch, glucan) and synthetic porous polymers (e.g., MOFs, COFs). Natural polymers like chitosan and dextran are biodegradable and biocompatible, while synthetic polymers offer tunable properties for targeted delivery. pH and glucose-responsive PNPs are particularly effective, as they can release insulin in response to physiological conditions. MOFs and COFs are also promising due to their high surface area, porosity, and functionalization capabilities. Research has shown that MOFs and COFs can encapsulate insulin efficiently and release it in response to stimuli such as pH and glucose levels. These materials have demonstrated high bioavailability and reduced toxicity, making them suitable for oral insulin delivery. However, challenges such as low loading capacity, stability, and scalability remain. Future research should focus on optimizing PNPs for better performance in oral insulin delivery systems.Polymeric nanoparticles (PNPs) are promising for oral insulin delivery due to their ability to enhance bioavailability and overcome challenges like gastrointestinal enzymes and pH variations. This review summarizes recent advancements in PNPs for oral insulin delivery, focusing on controlled release mechanisms, challenges, and future prospects. PNPs offer advantages such as stability, biocompatibility, and controlled drug release. They can protect insulin from degradation in the gastrointestinal tract and facilitate its delivery to the liver via the portal vein. PNPs are classified into natural polymers (e.g., chitosan, dextran, starch, glucan) and synthetic porous polymers (e.g., MOFs, COFs). Natural polymers like chitosan and dextran are biodegradable and biocompatible, while synthetic polymers offer tunable properties for targeted delivery. pH and glucose-responsive PNPs are particularly effective, as they can release insulin in response to physiological conditions. MOFs and COFs are also promising due to their high surface area, porosity, and functionalization capabilities. Research has shown that MOFs and COFs can encapsulate insulin efficiently and release it in response to stimuli such as pH and glucose levels. These materials have demonstrated high bioavailability and reduced toxicity, making them suitable for oral insulin delivery. However, challenges such as low loading capacity, stability, and scalability remain. Future research should focus on optimizing PNPs for better performance in oral insulin delivery systems.