The aim of this study is to investigate the tribological properties of castor oil with zinc oxide at different concentrations to improve the friction and wear characteristics of castor oil bio-lubricant as an alternative tribological lubricant. The treatment and disposal of petroleum-based lubricant waste presents considerable challenges for the oil manufacturing industry because of its effects on the environment. The use of vegetable-oil-based lubricant can solve such issues. Different from the previous studies, this study investigates the potential (wear and friction) of non-edible castor oil with additive for lubrication by comparing pure castor oil with different proportions of zinc additive to minimize wear and friction of engine components. In this study, an experimental bio-oil formulation from castor seed oil as base oil, Zinc as an additive is presented. This study was examined the tribological properties (wear and friction) of castor oil and its blends with zinc oxide. The experiments were perform using a Block on Ring tribometer with the standard test method ASTM G-77. Employing a block-on-ring tribometer, a series of experiments conducted to evaluate the friction and wear characteristics of pure castor oil versus its zinc oxide blends. The properties of the different samples of bio-oil formulations, such as the viscosity, penetration, drop point, wear and would be evaluated using standard methods, and the results would be compared to the blended oil with convectional diesel engine oil. The result of this study found that addition of ZnO to castor-based lubricant oil functions as an additive that decreases the friction coefficients and wear rates at specific loads for this study. When ZnO is used as an additive enhancement to the tribological properties of castor oil, when the concentration ratio is high (0.2%), it increases wear and COF. the wear rate versus ZO (%) added lubricant at 900 N, 1100 N, and 1300 N loads on the Block on Ring tribometer. When the concentration ratio is in the middle (0.15%), it reduces wear and COF. When the concentration ratio is too low, it reduces both wear and COF to some extent. Key Words: Bio-oil, Seed oil, Tribological properties, Viscosity, Penetration, Drop point Coefficient, Blended oil.