The objective of this study is to elucidate the relation between the results of ball drop tests and the residual stress distribution of an injection-compression molded part. To improve the ball drop property, a high impact material and a robust manufacturing process were employed. For the application to the transparent plastic window, it is of great importance to increase the impact strength of plastic products. Thin-walled plates were molded with use of rubber nanoparticles embedded poly(methyl methacrylate) (PMMA). Different compression gaps were considered during injection-compression molding (ICM) to adjust the residual stress distribution developed in the specimens. The ball drop tests were carried out to evaluate the impact strength of the prepared samples. In addition, the ICM was numerically simulated to predict the residual stress distribution in the parts.