Glucagon-like peptide-1 (GLP-1) receptor agonists are highly potent antihyperglycemic drugs that impose low risk of hypoglycemia and also result in body weight reduction. Currently, all approved members of the class require administration by injection. Areas covered: This manuscript reviews oral semaglutide-an experimental GLP-1 receptor agonist in phase-3 clinical development. Available pharmacological and clinical data of the drug are reviewed, and important end-points described. Expert opinion: Oral peptide delivery has become possible with the discovery of absorption enhancers. The clinical development program of once-daily oral semaglutide has shown superiority in reducing glycosylated hemoglobin and body weight in comparison with placebo and active comparators (sitagliptin, liraglutide, and empagliflozin). Safety and tolerability of oral semaglutide is in line with injectable members of the class. Delayed gastric emptying, local increase in pH, and enhanced absorption do not seem to affect the exposure of a number of other oral drugs that have been tested (metformin, digoxin, oral contraceptive ethinylestradiol/levonorgestrel, lisinopril, warfarin, furosemide and rosuvastatin). Clinical questions for further investigation include the effectiveness and safety of oral semaglutide in cardiovascular indications.