This study examined the local structural properties of Pt nanoparticles on SiO2, TiO2-SiO2, and ZrO2-SiO2 supports to better understand the impact of oxide-support type on the performance of Pt-based catalysts. In situ X-ray absorption fine structure (XAFS) measurements were taken for the Pt L-3-edge in a temperature range from 300 to 700 K in He, H-2, and O-2 gas environments. The XAFS measurements demonstrated that Pt atoms were highly dispersed on TiO2-SiO2 and ZrO2-SiO2 forming pancake-shaped nanoparticles, whereas Pt atoms formed larger particles of hemispherical shapes on SiO2 supports. Contrary to the SiO2 case, the coordination numbers for Pt, Ti, and Zr around Pt atoms on the TiO2-SiO2 and ZrO2-SiO2 supports were nearly constant from 300 to 700 K under the different gas environments. These results are consistent with the improvements in thermal stability of Pt nanoparticles achieved by incorporating TiO2 or ZrO2 on the surface of SiO2 supports. XAFS analysis further indicated that the enhanced dispersion and stability of Pt were a consequence of the strong metal support interaction via Pt-Ti and Pt-Zr bonds.