Abstract: Based on the first-order shear deformation theory (FSDT) a simple displacement-based, 20 DOF (5 DOF per node) quadrilateral bending element for the analysis of arbitrary laminated composite plates is presented in this paper. It is constructed through the following procedures: (i) the tangential rotation and the shear strain along each element side are determined by Timoshenko laminated composite beam theory. (ii) the shear strain and rotation fields within the element are then determined by improved rational interpolation. (iii) a bilinear in-plane displacement field is introduced for the coupling of in-plane and bending actions. The new element, denoted by TMQ20, is free of shear locking. It degenerates into the high-performance Mindlin plate element TMQ when dealing with single layer isotropic plates. Numerical examples to verify the proposed element for analysis of laminated composite plates will be presented in another paper published in the next issue of this Journal.