Use of fiber reinforced polymer (FRP) composites in seismic retrofitting of structural members has been steadily increasing in recent years. An important design issue with significant performance and safety implications is the debonding of externally bonded FRP reinforcement in flexural members. This paper provides the highlights of an experimental and analytical research aimed at understanding and modeling of debonding failures in FRP strengthened reinforced concrete beams. An evolutionary experimental program investigated debonding failure mechanisms and modes in beams strengthened in shear and/or flexure in various configurations and tested under monotonic and cyclic loading. A newly developed fracture mechanics based model considers the global energy balance of the system and predicts the debonding failure load by characterizing the dominant mechanisms of energy dissipation during debonding. Validation of the model is performed using experimental data obtained from several independent experimental studies.