The interaction of methanol with Cu/SiO2, ZrO2/SiO2, and Cu/ZrO2/SiO2 has been investigated by in situ infrared spectroscopy and temperature programmed desorption and reaction with the aim of understanding the nature of the species and the mechanism involved in methanol decomposition. In the case of Cu/SiO2, methanol exposure results in the formation of methoxide species on Cu and SiO2 at 323 K. In the absence of methanol in the gas phase, methoxide species on Cu are dehydrogenated to give formaldehyde starting at similar to 340 K and are oxidized to formate species at similar to 373 K, which then decomposes to CO2 and H-2 at similar to 390 K. When methanol is present in the gas phase, methyl formate, CO2 and H-2, resulting from the decomposition of methyl formate, are formed in addition to the above reactions. When ZrO2/SiO2 or Cu/ZrO2/SiO2 is exposed to methanol, the majority of the surface species observed are associated with zirconia. Methanol adsorption on either ZrO2/SiO2 or Cu/ZrO2/SiO2 leads to methoxide formation on zirconia and SiO2 at 323 K. In the presence of Cu, methoxide species on zirconia are dehydrogenated to give formaldehyde starting at similar to 325 K, which is oxidized to formate species on zirconia at similar to 373 K, which decompose to CO, CO2, and H-2 at similar to 400 K. Methyl formate and dimethyl ether are also observed to form above 460 K. In the absence of Cu, methoxide species on zirconia decompose only very slowly at 523 K. Metallic Cu is proposed to provide sites on which hydrogen atoms formed during the dehydrogenation of species located on zirconia can recombine efficiently and desorb as H-2. Thus, methanol decomposition over Cu/ZrO2/SiO2 is envisioned to occur primarily on ZrO2, with the primary function of Cu being the removal of hydrogen.