In this study, the effect of boron compounds on lubrication oils was investigated using a pin-on-disc type test apparatus. For this purpose, base oils containing two types of boron compounds were studied at different concentrations. The results were evaluated from the point of formation of a tribofilm in boundary or mixed lubrication conditions. The obtained results showed that the addition of boron compounds decreased the coefficient of friction from 10 to 50% under different test conditions. The optimum concentration ratio was determined as 4wt% for boric acid (H3BO3) and 4wt% for hexagonal boron nitride (hBN). Fuel consumption experiments were also carried out for both optimum concentration ratios using a 170-kW diesel engine. Results indicate a decrease of 3.6 and 2.7% in fuel consumption with boric acid and boron nitride additives, respectively.