<p>MXene–polymer nanocomposites have emerged as a promising new frontier in advanced corrosion-resistant coatings, driven by the unique properties of MXenes—two-dimensional transition-metal carbides and nitrides with high conductivity, hydrophilicity, and tunable surface terminations. These characteristics promote robust interfacial interactions with polymer matrices, aiding in uniform dispersion and augmenting mechanical reinforcement. Recent progress in MXene synthesis, including HF-based, molten-salt, electrochemical, and fluoride-free methods, has expanded material accessibility and improved structural stability. When incorporated into polymer coatings, MXenes create compact, tortuous pathways that impede the ingress of corrosive species, while polymers contribute flexibility, adhesion, and film-forming capability. This synergy results in improved barrier performance, mechanical robustness, and resistance to wear, fatigue, and thermal degradation. Electrochemical impedance spectroscopy (EIS), polarization testing, and salt-spray evaluations consistently show that these materials are better at preventing corrosion than traditional graphene- and CNT-based nanocomposites. Beyond corrosion resistance, MXene–polymer systems offer multifunctional advantages, including electrical conductivity, EMI shielding, flame retardancy, and antibacterial activity. However, challenges remain related to oxidation susceptibility, interfacial compatibility, environmental concerns, and scalable production. Ongoing developments in surface modification, hybrid architectures, and intelligent self-healing designs are expected to overcome these limitations, positioning MXene–polymer nanocomposites as strong candidates for next-generation high-performance protective coatings.</p>