<p>High-entropy alloy coatings (HEACs) have emerged as a promising class of protective materials, offering superior mechanical properties, oxidation resistance, and corrosion resistance compared to traditional coatings. A comprehensive understanding of the interplay between coating composition, preparation processes, microstructure, and properties is essential for advancing their practical applications. This review systematically explores how coating composition and preparation processes affect microstructure evolution and properties, establishing the connection between preparation, composition, microstructure, and properties of HEACs. Additionally, the review delves into the mechanisms that enhance wear resistance, corrosion resistance, and high-temperature oxidation resistance. Finally, the paper outlines future research directions, emphasizing potential applications in extreme environments and the need for further advancements in computational modeling, sustainable manufacturing, and high-throughput experimental techniques.</p> Graphical Abstract <p></p>