Zeolites are porous aluminosilicate minerals widely used as adsorbents or catalysts in a myriad of commercial petrochemical and environmental processes including production of transportation fuels (such as gasoline) and exhaust after-treatment of an end-pipe of a mobile (car or truck) or stationary source (industrial chimney). The process involves the diffusion of molecules through the zeolite pores to and from the active sites, which are often Brønsted acidic sites. The diffusion characteristics of the reactants and products determine the reaction kinetics of a reaction. The present study aims to understand the diffusion properties of methanol as a function of Brønsted acidic site density of zeolite H-ZSM-5, which is the part of methanol to gasoline (MTG) process. This information enables us to better understand and tune the MTG activity, product selectivity and catalyst stability.