Thermal oxidation of TaSi2 in dry oxygen and steam has been investigated. 0.3‐μm‐thick films of tantalum silicide were deposited by cosputtering on high resistivity 〈111〉 silicon and oxidized silicon wafers. After a crystallization anneal in argon, the films were oxidized in dry O2 or steam at 1000 and 1100 °C. In all cases oxidation was observed. For TaSi2 deposited on Si, only the growth of SiO2 was observed, indicating that the Si diffused through TaSi2 before oxidation, and TaSi2 remained intact. In the case where TaSi2 was deposited on SiO2, it was actively involved in the oxidation process, resulting in the formation of SiO2 and Ta2O5.