A high-performance, silicon oxycarbide (SiOC) aerogel material is suitable for use as thermal insulation at temperatures approaching 1,200 °C. These aerogel composites were created using cost-effective and commercially available polymeric precursors (the polymethylsiloxane resin, SOC-A35, from Starfire Systems), thus enabling scaleup and mass commercialization. The SiOC aerogels exhibited bulk densities and thermal conductivities that rival traditional silica-based aerogels. Prolonged exposure to temperatures above 1,000 °C had virtually no effect on the thermal conductivity, surface area, pore volume, or pore diameter of SiOC aerogels.