Due to their non-corrosive nature, high strength and light weight, fiber reinforced polymers (FRP) are being widely used as reinforcement in concrete bridges, especially those in harsh environments. The current design methods of concrete deck slabs in most bridge design codes assume a flexural behavior under traffic wheel loads. The load carrying capacities of concrete bridge deck slabs, however, are greatly enhanced due to the arching action effect developed by lateral restraints. This study presents the results of a non-linear finite element (FE) investigation that predicts the performance of FRP reinforced concrete (RC) deck slabs. The FE investigation is divided into two main parts: a calibration study and a parametric study. In the calibration study, the validity and accuracy of the FE model were verified against experimental test results of concrete slabs reinforced with glass and carbon FRP bars. In the parametric study, the effect of some key parameters influencing the performance of FRP-RC deck slabs bars was investigated. These parameters include the FRP reinforcement ratio, concrete compressive strength, slab thickness and span-to-depth ratio.