This study investigated the mechanical performance of short aramid fiber on polypropylene, polyethylene, polyamide 6, and polyamide 12. Extrusion, press molding, and CNC cutting methods were used in the production of composite samples. Tensile, three-point bending, drop weight and hardness tests of the composites were carried out. As the fiber volume fractions increased, the mechanical properties of the composites improved, but the most efficient fiber fractions for each matrix changed. To analyze the performance of the fibers in the matrix on the composites, scanning electron microscope (SEM) images of the fractured surfaces as a result of tensile and drop weight tests were examined. As the fiber volume fractions increased, the fiber deformation increased, and as a result, the mechanical performance of the composites was adversely affected. Analysis of variance (ANOVA) and F test were performed using signal/noise values to analyze in detail the effect of experimental parameters on output values. Finally, the results of a regression equation model were compared with the experimental readings. It was found to be in good agreement with the model and the results of the experiment.