Insulated sandwich panel consists of face layers separated by foam insulation cores. Existing studies are mainly focused on two-layers sandwich panel. Multiple layers can also be used to increase the panels’ strength and improve their energy performance. This article presents an analytical solution for multi-layers insulated sandwich panels with flexible shear connectors, such as Fiber-Reinforced Polymer (FRP) shear connectors. For flexible shear connectors, the slip between layers leads to partial Degree of Composite Action (DCA), which is considered in the analytical solution. The analytical results are verified with Finite Element (FE) analyses. Finally, a multi-layers sandwich panel application is presented.