The effect of reinforcement anchorage on the seismic loading behavior of external RC beam-column connections reinforced with GFRP bars has not yet been deeply studied in the scientific community. In the case of GFRP bars, there are restrictions when using standard 90° hooks to achieve the required anchorage length in external joints, which currently limits the length of the straight part of the bent bar, due to the reduced tensile strength of bent GFRP bars. For this reason, the present study analyzes the influence of the parameters: anchorage length and type of anchorage of the reinforcement using straight bars and bars bent at 90° on the seismic loading performance of reinforced concrete beam-column external connections with FRP bars through the use of numerical modeling techniques. For this purpose, a mathematical-computational model based on the Finite Element Method implemented with the ABAQUS/CAE software version 2017 and calibrated with full-scale tests is developed. It is concluded that as the anchorage length of the GFRP reinforcement increases, the seismic loading performance of the connection is favorably modified and that the type of anchorage of the reinforcement using straight bars and 90° bent bars has a significant influence on the seismic resistant behavior of the connection related to the upper drifts.