Face sheet/core disbonding undermines the structural integrity of a sandwich component. A methodology to predict onset and growth of face sheet/core disbonding is presented in this work. The proposed methodology is similar to the one used to predict delaminations in monolithic composite laminates, wherein an assessment based on measuring critical strain energy release rate is conducted. In general, two steps are required to address the phenomenon associated with the face sheet/core disbonding. First, a reliable method to characterize the face sheet/core disbonding must be established. In that line, the Single Cantilever Beam (SCB) fracture test has been identified as the most appropriate configuration to develop an ASTM standardized test method to determine the Mode I dominant fracture toughness of typical sandwich constructions. In addition, a guidance for the development for Mode I fatigue based on the static SCB test is proposed here. Further, a Sandwich Mixed-Mode Bending (S-MMB) test for mixed-mode I/II fracture toughness of sandwich constructions based on the existing ASTM MMB test method for laminates, D6671, is suggested. Second, analysis methods are needed to assess the likelihood of a structure exhibiting critical disbonding. To illustrate, the Crack Surface Displacement Extrapolation (CSDE) method was employed to assess disbond growth in a sandwich panel containing an artificial disbond and the predicted growth was compared to test results. In addition, a rapid engineering analysis tool based on energy-based Rayleigh-Ritz approach is also discussed.