The analysis of residual stresses generated during the injection molding process is crucial for the part quality assessment. The present study evaluates the generation of residual stress considering different variables that affect them. For that purpose, diverse part geometries were evaluated with different polymers (polycarbonate, ABS and polypropylene) and some Design of Experiments (DOE) were implemented in a simulation software of injection molding process (Moldex 3D). The results show higher residual stresses in thick wall parts due to unbalanced cooling through-thickness. For thin-wall parts, residual stresses were lower because of better cooling through its thickness. The polycarbonate was the more sensitive polymer to residual stresses upon its processing conditions, being the mold temperature and the packing stage the most critical variables to increase or reduce residual stresses.