<p>Reinforced concrete (RC) beams may require flexural strengthening due to many reasons. In this regard, various systems have been utilized, and the selection of the optimum one is a big challenge among researchers and practicing engineers. The core goal of this research is to come up with the most efficient upgrading technique by conducting a comprehensive comparison between different systems that are added on the tension side of the beams without increasing their dimensions. This study was conducted using nonlinear finite element (FE) analysis. The FE matrix was comprised of two phases in which a total of 19 RC beams were numerically analyzed under four-point flexure. In the first phase, seven specimens were modeled, and they incorporated one unstrengthened reference beam, in addition to six upgraded beams. Strengthening schemes involved the use of NSM (near-surface-mounted) reinforcement such as steel bars, GFRP (glass fiber-reinforced polymer) bars, CFRP (carbon fiber-reinforced polymer) bars, and pultruded CFRP plates, in addition to externally bonded CFRP sheets and TRM (textile-reinforced mortar) layers. The different schemes were designed to have nearly the same flexural capacity increase. In the second phase, 12 upgraded beams were numerically simulated to conduct a parametric study for exploring the influence of various strengthening factors. With regard to key performance parameters, the most efficient upgrading system was NSM steel bars with a recommendation of using FRP U-wrap anchorage at the ends of NSM bars. As a compromise between the evaluation parameters, it is recommended to arrange the upgrading systems in the order of reducing efficiency as follows: NSM steel bars, NSM GFRP bars, NSM CFRP bars, NSM CFRP plates, CFRP sheets, and TRM composites.</p>