This chapter presents the direct boundary element formulation of isotropic Reissner plates. The Reissner plate theory and governing equations for shear deformable plates are presented. Based on these equations, the boundary integral formulation is developed. Fundamental solutions for displacements and tractions for infinite elastic plane under transversal loads and in-plane bending moments are showed. Boundary element method is applied to discretizate the integral boundary equation. Procedures for treatment of the singular integrals are showed. Finally, numerical examples are showed and results are discussed.