We discuss the synthesis of a composite of ZrO2nanoparticles supported on multiwalled carbon nanotubes (MWCNT). Using X-ray diffraction and high-resolution transmission electron microscopy (HR-TEM), the ZrO2were found to be 2–3 nm tetragonal crystalline nanoparticles. Strong interfacial interaction between the ZrO2nanoparticles and the MWCNT surface was observed by near-edge X-ray absorption fine structure spectroscopy (NEXAFS) at the carbon K-edge and the oxygen K-edge, and this strong metal oxide/support interaction leads to small ZrO2particle size and thermal stability. The ZrO2/MWCNT was converted into a solid acid catalyst by sulfation, and the properties of S-ZrO2/MWCNT were studied. The nature of the acid sites was probed by S K-edge and Zr L-edges (L3, L2, L1) XANES as well as catalytic probe reaction of cyclohexane dehydrogenation/cracking. Such composites would be good candidates for potential catalysis applications in fuel cell electrodes and biomass processing.