Nanocrystalline alumina was prepared and was employed as a support for vanadium catalysts. The catalysts were characterized by N-2 adsorption/desorption, X-ray diffraction, TPR, UV-Vis, NH3-TPD, and CO2-TPSR. The activity and selectivity of the catalysts in ethylbenzene dehydrogenation in the presence of CO2 were compared with vanadium supported on commercial available alumina. The catalytic activity, selectivity, and stability were enhanced by the use of nanocrystalline alumina as catalyst supports. The superior performance of the present nano-crystalline alumina catalysts was attributed to the higher surface areas, higher vanadium dispersion, and higher stability of V5+ against reduction.