The previous explanations on buckling of composite laminates only allow the consideration of laminates in which no transverse shear deformations occur. However, in many practical applications, layups with anisotropic properties and bending-twisting coupling are employed in which such shear deformations play a decisive role in the buckling response. This chapter is therefore dedicated to the development of the Ritz method for various laminate situations under consideration of transverse shear strains, based on the First-Order Shear Deformation Theory (FSDT) and the Third-Order Shear Deformation Theory (TSDT) (see also Mittelstedt and Mittelstedt (2019)).