We have studied interfaces ofn‐InSb with SiO2films, obtained by low‐temperature chemical vapor deposition, using capacitance‐voltage measurements and Auger electron spectroscopy (AES). Improvements of electrical properties of MOS capacitors based on this system were sought by various pre‐ and post‐treatments. The results show that a methanol pre‐treatment causes significant improvements in the flat‐band voltage (VFB) of metal‐oxide‐semiconductor capacitors based on this system. In addition, thermal post‐annealing in oxidizing atmospheres also improvedVFB. AES reveals that at the SiO2‐InSb interface there is a native oxide interlayer, the width of which was found to be reduced by a factor of 2–3 due to the specified treatments. Therefore, we attribute theVFBimprovement to the reduction in the density of charges and traps due to the narrowing of the interfacial native oxide, in agreement with other recent results.