Polymer-derived SiOC/ZrO2 ceramic nanocomposites have been prepared using two synthetic approaches. A commercially available polymethylsilsesquioxane (MK Belsil PMS) was filled with nanocrystalline zirconia particles in the first approach. The second method involved the addition of zirconium tetra(n-propoxide), Zr((OPr)-Pr-n)(4), as zirconia precursor to polysilsesquioxane. The prepared materials have been subsequently cross-linked and pyrolyzed at 1100 degrees C in argon atmosphere to provide SiOC/ZrO2 ceramics. The obtained SiOC/ZrO2 materials were characterized by means of X-ray diffraction, elemental analysis, Raman spectroscopy as well as transmission electron microscopy. Furthermore, annealing experiments at temperatures from 1300 degrees to 1600 degrees C have been performed. The annealing experiments revealed that the incorporation of ZrO2 into the SiOC matrix remarkably increases the thermal stability of the composites with respect to crystallization and decomposition at temperatures exceeding 1300 degrees C. The results obtained within this study emphasize the enormous potential of polymer-derived SiOC/ZrO2 composites for high-temperature applications.