The FeCoNiCrMn high-entropy alloy (HEA) has attracted considerable attention in materials science owing to its outstanding wear resistance and corrosion resistance, rendering it highly suitable for diverse industrial applications. This study examines the effect of tungsten carbide (WC) particle size on the microstructure and properties of FeCoNiCrMn HEA coatings fabricated by laser cladding on a 1.0503 steel substrate. The findings reveal that the coatings predominantly comprise a face-centered cubic (FCC) phase, while the addition of WC particles facilitates the formation of the M6C phase. Furthermore, the concentration of the M6C phase increases with decrease in WC particle size. The incorporation of WC particles refines the microstructure of the coatings, strengthens interfacial bonding, and diminishes the formation of macroscopic pores and cracks. These effects are more pronounced with finer WC particles. Specifically, smaller WC particles markedly enhance the microhardness of the coatings, reduce the friction coefficient and wear rate, thereby improving wear resistance. However, the introduction of WC particles results in a decline in the corrosion resistance of the coatings and a gradual increase in residual surface stress, with these effects becoming more pronounced as the particle size decreases. In summary, this study demonstrates that optimizing the WC offers valuable insights for their industrial applications.