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A series of commercially available γ-Al 2 O 3 samples were tested for vapor-phase dehydration of methanol to dimethyl ether (DME). The samples were characterized using X-ray diffraction (XRD), temperatureprogrammed desorption of ammonia (NH 3 -TPD), and Brunauer-Emmett-Teller (BET) surface area techniques. The catalysts were determined to be highly amorphous with similar porous structures. Catalyst screening tests were performed in a fixed-bed reactor under the same operating conditions (temperature, T ) 573 K; pressure, P ) 16 bar (gauge); weight hourly space velocity, WHSV ) 26.07 h -1 ). The influence of operation conditions on catalyst performance, as well as the stability of catalysts toward water, was also studied. It was determined that γ-Al 2 O 3 catalysts with acidic sites whose acidity is very weak and/or moderate exhibit the best catalytic performance and stability. A new kinetics expression was developed for the dehydration of methanol to DME. The kinetics was observed to fit the experimental data accurately. An activation energy of 57.7 kJ/mol was obtained for the catalyst with the best performance.