Diabetes mellitus is a lifelong metabolic disease that requires frequent subcutaneous injections of insulin. However, this method of administration can be associated with patient discomfort and local tissue infection. Oral delivery of insulin has been pursued as a more convenient method for diabetes treatment, given its likely superior patient compliance and convenience as well as cost‐effectiveness. However, various biological barriers hinder the clinical translation of oral insulin. The rapid development of nanotechnology over the last decade offers great promise in improving the bioavailability of oral insulin. This Minireview provides an overview of biological barriers to oral insulin delivery, summarizes significant technological advances, and outlines future perspectives in oral insulin formulations as well as their hypoglycaemic effects. Oral insulin delivery holds great promise as a convenient and economical means of diabetes treatment. This Minireview provides an overview of representative advances in facilitating oral insulin delivery by overcoming biological barriers, including strategies centered on moieties‐mediated transport, cell‐penetrating peptide assisted permeation, smart oral robotics transport, and microenvironment‐responsive release.