 Oral insulin administration is limited by gastrointestinal enzymes and mucus layers, resulting in low bioavailability. Polymeric nanoparticles, PNPs, have shown promise for increasing oral insulin delivery with controlled release mechanisms and promising applications. This review summarizes the latest PNPS-based oral insulin delivery systems, challenges and prospects, serving as a guide for future investigators in this field. This article was authored by Union Wang, Hao Li, Ameira Su, and others.