The flexural plastic hinge (PH) length is a critical parameter for reinforced concrete (RC) frames subjected to lateral load. In this work, a review of past studies for introducing empirical equations for estimating the flexural PH length (lp) of RC frames was introduced. Another key aspect explored in this paper is to study the effect of different available lp equations on the overall nonlinear structural response of RC frames. Therefore, ten lp equations were selected from this review for simulating the nonlinear behavior of two RC frames with available experimental data. Each frame was analyzed ten times with alternative lp values under pushover analysis using SAP2000 software. The two modeled frames displayed an average error ranging from 12.3% to 23% in the ultimate lateral load, and a deviation ranging from -30.4% to 20.1% in the initial lateral stiffness. These errors indicated that the accuracy of predicting the behavior of RC frames is highly dependent on the chosen lp equation. Finally, the proper lp equation which could represent the nonlinear behavior of RC frames accurately was recommended.