In this research, effects of screw diameter, screw type, panel type, and end distance on lateral resistance of the joints made with drywall and sheet metal screws were studied in bagasse particleboard and the results were compared to those obtained from commercial medium density fiberboard (MDF). The accuracy of EYM in prediction of lateral resistance was then investigated. The drywall screws comprised of size 8 with coarse thread and size 10 with fine thread; the sheet metal screws comprised of size 8 and 10 with normal thread. Results indicated that lateral resistance increased with the increase in the diameter of both screw types, although not statistically significant. The lateral resistance obtained from MDF specimens was 20% more than that of bagasse specimens. Increase in the end distance also resulted in an increase in the lateral resistance. In all cases, sheet metal screws showed higher lateral resistance in comparison to those obtained from drywall screws. It can be concluded that Mode IIIs is more accurate than Mode Is in the prediction of lateral resistance in two-member screwed joints (single shear plane) for both MDF and bagasse boards.