The interaction of process parameters in the production of polyvinyl chloride-grass composite poses great challenges in the polymeric industries. Most manufacturing processes of injection moulded polyvinyl chloride-grass composite products have been by trial and error due to inadequate knowledge in process parameters and their interactions. This study investigates the effects of process parameters such as percentage by volume of material, material type, barrel temperature and their interactions on the mechanical properties of the produced polyvinyl chloride-grass composite using split-split plot design. The results of the calculated Fisher's ratio (F_cal) at significant value of 0.05 for the process parameters and their interactions ranges from-855.35 to 1.00, and were presented on ANOVA table. The results obtained shows that these process parameters contribute significantly to the production of Polyvinyl chloride-grass composite in polymeric industries.