In this paper, a Cohesive Model-Based Approach framework for predicting the flexural behavior of reinforced concrete (RC) beams strengthened with Basalt fiber-reinforced polymer (BFRP) sheet is presented. The proposed model is based on the mixed-mode constitutive of the FRP-concrete interface, the concrete potential fracture surfaces, and the rebar-concrete interface. The normal separation of the interface and its coupling effect on the shear behavior are considered constitutive. In this model, all failure modes of RC beams strengthened with BFRP sheets were incorporated with emphasis on a premature failure mode which is an intermediate crack-induced debonding. The model framework is a combination of several failure criteria that is established experimentally. The proposed model is then verified against an experimental database of several RC beams strengthened in flexure with FRP sheets assembled from previous updated research with various configurations and failure modes. The verification results between theoretical and experimental data showed that the proposed model accurately predicts the flexural behavior of strengthened RC beams at different loading levels and gives an acceptable prediction of the load-bearing capacity as well as the failure modes of the strengthened beams.