Target-specific drug-delivery systems for the administration of pharmaceutical compounds enable the localization of drugs to diseased sites. Various types of drug-delivery systems utilize carriers, such as immunoglobulins, serum proteins, synthetic polymers, liposomes, and microspheres. The vesicular system of niosomes, with their bilayer structure assembled by nonionic surfactants, is able to enhance the bioavailability of a drug to a predetermined area for a period. The amphiphilic nature of niosomes promotes their efficiency in encapsulating lipophilic or hydrophilic drugs. Other additives, such as cholesterol, can be used to maintain the rigidity of the niosomes’ structure. This narrative review describes fundamental aspects of niosomes, including their structural components, methods of preparation, limitations, and current applications to various diseases.