The reaction of Fe(acac)3 with the surface of zirconia has been studied for the first time using in situ infrared diffuse reflectance spectroscopy, photoacoustic spectroscopy, and Fourier transform Raman spectroscopy. The unstable Fe(acac)3 reacts readily with the surface of zirconia at room temperature in the liquid phase or at 110 C in the gas phase, yielding grafted Fe-OH species and Zr-acac surface groups. We present evidence that the reaction occurs both with coordinatively unsaturated Zr sites and with the surface hydroxyls. The grafted Zr-acac groups are thermally unstable and form Zr-acetate groups after thermal treatment at 110 C in ambient air. After removal of the organic ligands, noncrystalline iron oxide species are formed on the zirconia surface. The grafting of iron oxide on zirconia is a relevant procedure to form either redox catalysts or solid-state fuel cells.