The present paper discusses the hygro-thermo-mechanical behavior of multilayered composite and sandwich plates based on a Layerwise Displacement (LD) approach using the Carrera's Unified Formulation (CUF). Legendre polynomials and a new proposed trigonometrical shear strain shape function are evaluated within a compact shear deformation formulation. Hygro-thermo-mechanical loads are applied considering linear and calculated profiles solved by the Fick moisture diffusion law equation and the Fourier heat conduction equation. The Navier solution method was used to solve the governing equations obtained by the principle of the virtual displacement (PVD). Results are in good agreement with published results in the literature. Some bending problem benchmarks considering hygro-thermo-mechanical loads applied in a coupled manner are presented.