In the present study, the effect of material properties AND SLENDERNESS ratios on the nonlinear behavior characteristics AND energy dissipation behavior of steel plates (including stainless steel, mild structural steel AND low yield point steel) under shear loading is studied using FEM. First, the steel shear plates with respect to their SLENDERNESS ratio AND nonlinear behavior are qualitatively AND quantitatively classified into very slender, slender, moderate, stocky AND very stocky. To quantitatively determine the SLENDERNESS classes for each steel materials, modified theoretical relationships are presented separately using statistical analyses of the obtained results for various steel plates. Also, new relationships for assessment of inelastic (moderate plates) AND plastic (stocky plates) buckling loads are proposed, that can estimate buckling loads for moderate AND stocky plates more accurately compared to the available theoretical relationships in AASHTO. In general, with increasing SLENDERNESS ratio, the capability of steel plates for energy dissipation, due to the occurrence of buckling AND the resulted pinching in the hysteresis loops, is gradually decreased. In the case of very stocky plates, the capability of plates for energy dissipation is only dependent on the material yield stress, while in the class of slender, moderate AND stocky plates, it is dependent to both of the SLENDERNESS ratio AND material yield stress. In the case of very slender steel plates, the capability of different steel plates for energy dissipation, disregarding the material yield stress AND the plate SLENDERNESS ratio, seems to be similar, less or more, for various steel materials.