 This narrative review examines the factors influencing the adherence to multivitamin supplementation, MVS, after bariatric surgery. It considers the various factors that may affect patient compliance with taking MVS, including demographic characteristics, psychological factors, and healthcare system factors. The review concludes that there is a need for further research into the effectiveness of MVS in improving outcomes following bariatric surgery. This article was authored by Hendricka J.M. Smelt, Jack Pools, Johannes F. Smeltas, and others.