Abstract <p>This review summarizes recent advances in the synthesis and application of quantum dots (QDs) for the corrosion protection of metallic materials and for corrosion monitoring. Particular attention is paid to the dual functionality of these nanomaterials as effective corrosion inhibitors and as highly sensitive fluorescent sensors capable of early detection of corrosion processes. The mechanisms of the inhibitive action of QDs in acidic and saline media are discussed, including adsorption, formation of protective films, and blocking of anodic and cathodic reactions. Data on the influence of chemical composition, particle size, and type of doping (N-, S-, and P-doped dots, carbon dots (CDs)) on inhibition efficiency—reaching up to 97% in aggressive environments—are summarized. Comparative characteristics of the inhibition efficiency of quantum dots in acidic (HCl, H₂SO₄) and saline (NaCl) solutions are presented for steel, aluminum alloys, and copper. The advantages of carbon dots are highlighted, including high biocompatibility, low toxicity, water solubility, thermal stability, and relatively high environmental safety. In addition to their inhibitive function, additional properties of CDs—such as optical activity and sensitivity to metal ions—are considered, which can be exploited for integration into “smart” protective coatings. The review focuses primarily on the inhibitive performance of nanoparticles and their application as alternatives to conventional anticorrosion agents. Analysis of data from diverse scientific literature sources underscores the potential of carbon quantum dots as components of next-generation intelligent anticorrosion systems that combine inhibition, self-diagnostics, and visual monitoring.</p>