Plasma electrolytic oxidation (PEO) is an advanced electrochemical and plasma-assisted technology employed for the development of multifunctional ceramic coatings on light metals, outstanding aluminum and magnesium alloys. Although these alloys are widely employed in diverse industries, like automotive, aerospace, or biomedical sectors, their low tribological resistance currently limits their use in more demanding applications. In this context, the development of PEO coatings provides an effective solution to these challenges by offering excellent adhesion to the substrate, high hardness, and enhanced wear resistance. Research in recent years has demonstrated the feasibility of PEO technology to improve the tribological properties of Al alloys, with outstanding results even on cast Al-Si alloys, whose composition is challenging. On the other hand, although PEO coating research on Mg alloys has been mainly focused on the improvement of the corrosion resistance, increasing studies are showing the potential of PEO coatings for the tribological improvement of Mg alloys, especially through the incorporation of nanoparticles into the layers. These advances have established PEO technology as a sustainable and versatile surface solution, broadening the application of Al and Mg alloys in high-performance environments.