Polymeric gas separation membranes have found widespread application particularly for CO2 capture and natural gas sweetening. Permeability through these membranes depends on solubility (S) and diffusion (D) coefficients of the gas penetrants, for which estimation of the molar heat of sorption (Delta H-S), is of high importance to attain the S value. A well-known linear empirical correlation to predict Delta H-S in rubbery polymers, has been already proposed by van Amerongen [Rubber Chem. Technol. 1964, 37, 1065]. In this paper, a correlation based on the physical properties of the gas penetrants and polymers has been provided as a basis for the extensively applied Delta H-S correlation for the glassy polymers in the literature developed according to van Amerongen's empirical method. The proposed correlation, takes into account the contribution of the polymer nature, which is more distinct for small molecule, highly supercritical gas solutes, that is, much above their critical temperatures, such as H-2 and He. It was found that the physical properties of the penetrants play a significant role in the Delta H-S calculation. The developed correlation was satisfactorily validated for various gases including CO2, CH4, C2H4, C2H6, C3H6, C3H8, C4H10, SO2, O-2, He, H-2, and N-2, and glassy polymers consisting of poly(vinyl acetate) (PVAC), poly(ethylene terephthalate) (PETP), poly(vinyl chloride) (PVC), and polycarbonate (PC).