In the last two decades, researchers and engineers studied the possibility of reinforcing slabs and beams with fiber-reinforced polymer (FRP) bars instead of the conventionally used steel reinforcement. Such FRP bars have high strength and corrosion resistance properties. However, the fire resistance of reinforced concrete (RC) members is still a concern when reinforced with such materials. The major objective of this paper is to develop a 3D finite element (FE) model and perform nonlinear thermal-stress analysis to predict the fire performance and time to failure of concrete beams reinforced with GFRP bars. The developed model includes temperature-dependent thermal and mechanical material properties. The predicted fire resistance of the beam specimen is compared with published experimental data. The numerically predicted and measured experimental results are in close agreement. The developed FE model would be used as a valid tool to study the effect of key parameters on the fire performance of RC beams reinforced with FRP bars.