Sandwich composites with nanoreinforced polypropylene core and aluminum face sheets were studied under low velocity impact using a finite element model. A three dimensional quarter model was implemented to simulate the drop weight impact response of sandwich structures. In order to consider the strain rate dependent behavior of the core and face sheets, the Johnson–Cook material model was used for both of the polypropylene and aluminum layers. Effects of the different weight ratio of nanoparticles, the core thickness and the impactor mass were studied on the impact outputs. Comparing the impact responses of the sandwich structures with different weight ratio of nanoparticles revealed that positioning a polypropylene layer with 0.5% weight ratio of graphene as the core of sandwich panel caused the minimum amounts of damage area and transverse displacement. Adding more amount of nanoparticles did not improved the mechanical response of the sandwich structures. Increasing the impactor mass caused an increase of the contact force and the contact duration. Increasing the core thickness caused a decrease of the contact duration and increase of the contact force. The finite element outputs were well validated against the experimental results.