Postbiotics are preparations containing inanimate microorganisms or their components that have a direct or indirect beneficial effect on the host and can include many different components, such as short-chain fatty acids, bacterial lysates, cell-free culture supernatants, cell wall fragments, enzymes, and exopolysaccharides. Despite the numerous advantages of postbiotics for the body, their use is limited due to unfavorable pharmacokinetics, low bioavailability, non-selective pharmacological action, poor palatability, and unpleasant odor. The development of nanotechnology-based delivery systems could be an important industrial tool to enhance the selective action of these agents and improve their therapeutic efficacy, particularly in the pharmaceutical and food sectors. In the pharmaceutical industry, several nanotechnology-based delivery systems have already been approved by the FDA and successfully marketed, demonstrating their clinical and industrial viability, such as Abraxane®, Doxil® (or Caelyx®), Onivyde®, Marqibo®, and Vyxeos®. In the food industry, products such as Driphorm® (nanostructured lipid emulsion for the efficient delivery of vitamin D in food) illustrate how nanotechnology has been applied in concrete ways to the development of functional foods and nutraceuticals, contributing to technological innovation, added value, and advances in health promotion. However, although nanotechnology in the delivery of postbiotics is an emerging and innovative field with promising preclinical studies, the lack of consolidated clinical or commercial data means that this topic needs to be expanded in order to achieve standardization and clinical validation. This review aims to highlight the importance of postbiotics in the modulation of gut microbiota and in the prevention/treatment of disease, as well as the potential of using nanotechnology to facilitate the targeting of these compounds and the limitations of using these systems for such applications.