In this research work, pulverized biochar obtained by the pyrolysis of rice husk is used as particulate reinforcement in unsaturated polyester matrix. The effects of the particle loading and particle size on tribological properties of the particulate composites were investigated. The average size of biochar particles obtained through pulverizing using ball-mill varied from 510 nm to 45 nm while milling for a duration ranging from 6 hrs to 30 hrs. The particle loading in the composite was varied from 0.5 wt.% to 2.5 wt.%. It was observed that the particle size and particle content played a vital role in the tribological properties of the composites. The specific wear rate of the specimen having particle loading of 2.5 wt.% with 45 nm particle size exhibited a decrease of 56.36% upon comparing with the specific wear rate of cured pure resin. The coefficient of friction of the same sample decreased by 6.42% when compared to that of a cured pure resin. The biochar particles were subjected to X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and atomic force microscope analysis for characterization. Morphological studies were performed on the worn surfaces by scanning electron microscope (SEM) and optical microscopy.