<p>The tribocorrosion resistance of CrFeCoNi high-entropy alloys (HEAs) was systematically studied through controlled addition of cerium (Ce) in 0.9 wt% NaCl solution. Alloys with varying Ce contents were fabricated by arc-melting and evaluated under open-circuit potential and reciprocating sliding wear conditions. Among the investigated alloys, the Ce_0.02 alloy exhibited enhanced performance, with the lowest coefficient of friction (0.373) and wear rate (5.35 × 10⁻⁷ mm³/N·m), significantly surpassing the Ce-free alloy. Additionally, the Ce_0.02 alloy outperformed the Ce-free alloy in dry sliding wear. Surface analysis revealed that Ce addition promoted the formation of a dense, Cr₂O₃₋ and CeO₂-enriched passive film, thereby enhancing repassivation kinetics and improving surface stability during mechanical disruption. However, excessive addition of Ce resulted in passive film instability and degradation in alloy performance. The results demonstrate that the optimized Ce content effectively improves surface chemistry and wear durability, providing guidance for the design of HEAs for use in tribological environments (saline and marine).</p> Graphical Abstract <p></p>