<p>Valorization of waste coconut cooking oil (WCCO) is of special interest as it is cheaper than vegetable oils and can be reused to drastically lower biodiesel feedstock costs. Also, tribology-related issues arise from the use of WCCO biodiesel in diesel engines. This investigation is intended to evaluate the performance and emission behavior of diesel engines and the tribological characteristics of different blends of WCCO biodiesel. A two-stage transesterification was used to synthesize WCCO biodiesel. WCCO biodiesel was blended with diesel at 10, 20, and 30% volume percentages. To assess the influence of WCCO biodiesel, an engine performance test was conducted on a single-cylinder diesel engine, and tribological tests were performed using a four-ball tribometer. For all the WCCO biodiesels, the engine brake thermal efficiency was marginally lower than diesel. Twenty percent by vol. of WCCO biodiesel blend had lower CO, HC, and CO₂ emissions while 100% by vol. of WCCO biodiesel had lower NO_x emissions when compared to all other fuels. WCCO biodiesel’s wear scar diameter seemed to be 28.3% lesser than diesel’s, and anti-friction behavior improved as biodiesel concentration increased. The value-added conversion of WCCO demonstrates its effectiveness and could lead to extensive use in the production of biodiesel.</p>