The adsorption of methanol (CH3OH) and water (D2O) on the MgO(100)/Mo(100) surface at 100 K has been studied by metastable impact electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS (HeI)), and temperature programmed desorption (TPD). To acquire detailed information regarding the initial stages of adsorption, TPD data, providing information about the relative surface coverage and the molecule-surface interaction, are compared directly with MIES data, which provide information about the electronic structure of the adsorbed molecules. For water adsorption, a prominent multilayer desorption feature develops in the TPD before the entire surface is covered, indicating 3D growth on the partially covered MgO(100)/Mo(100) surface. On the other hand, the formation of a methanol multilayer desorption feature coincides with complete coverage of the surface.