•Drop-weight impact tests were performed on steel or GFRP bars RC slabs.•Effects of bar type, reinforcement ratio and arrangement were investigated.•Effects of concrete strength and slab thickness were also investigated.•Singly RC slab with higher tensile bars than doubly RC slab perform better.•The results obtained from experiment and numerical simulation are in good agreement. Reinforced concrete slabs are common structural elements that could be exposed to impact loading. Although use of reinforced concrete slabs and utilization of Fiber Reinforced Polymer (FRP) as alternative to traditional steel reinforcement slabs are growing, but the influence of various parameters on their response under impact loads is not properly evaluated. This study investigated the effect of rebar’s material, amount and arrangement of reinforcements, concrete strength and slab thickness on dynamic behavior of reinforced concrete slabs using both laboratory experiments and numerical simulations. Performance of fifteen 1000 × 1000 mm concrete slabs, including two 75 mm thick plain slabs, five 75 mm thick steel reinforced concrete slabs, six 75 mm thick reinforced concrete slabs with Glass Fiber Reinforced Polymer (GFRP) bars and two 100 mm thick steel reinforced concrete slabs under drop weight impact loads was experimentally investigated. Failure mode, crack development, displacement-time, strain-time, and acceleration-time responses were studied and compared between various slabs. Finite element analyses and simulation of specimens were conducted using LS-DYNA explicit software. The results obtained from experiments and numerical models are in good agreement, and they indicate that increasing the reinforcement ratio or the slab thickness enhance the behavior of RC slabs under impact loads. By adjusting the amount and arrangement of GFRP, better performance in GFRP slabs than steel reinforced slabs can be achieved, which considering the corrosion resistance of this material, can make it an appropriate selection of reinforcement material.