This paper contained the free vibration analysis of folded plate based on First-Order Shear Deformation Theory (FSDT) and Finite Element Method (FEM) accordingly. Sandwich materials with E-glass epoxy skin and polyurethane core have been considered for this study. Layer-wise model with nine-noded Lagrangian plate bending element has been used. The cantilever boundary restraint, at different orientation, has been applied to determine the fundamental frequency and mode shape of the structure. The paper contained the validated results with the existing literature. Parametric studies have been carried out with the variation of different parameters, i.e. core-to-skin thickness ratio, side-to-thickness ratio, boundary conditions and various symmetric and anti-symmetric lamination angles. Result of research shows that vibration characteristics of folded plate structures are greatly influenced by the said parameters. The effect of symmetric or anti-symmetric lamination scheme in face sheets poses very little changes in vibration pattern.