The desirable electrical properties of InO<sub>x</sub> thin films and their response towards oxidizing gases has promoted InO<sub>x</sub> to be recognized as a promising material for gas sensors. In this study, InO<sub>x</sub> films in the thickness range of 10-1000 nm were deposited onto Corning 7059 glass substrates by dc magnetron sputtering. Their structural, electrical, and O<sub>3</sub> and NO<sub>2</sub> sensing properties were analyzed. Structural investigations carried out by XRD and AFM showed a strong correlation between crystallinity, surface topology and gas sensitivity. Moreover, the electrical conductivity exhibited a change of over six orders of magnitude during the processes of photoreduction and oxidation. The films deposited on alumina transducers were calibrated towards O<sub>3</sub> and NO<sub>2</sub> at temperatures from 50-300 °C. The sensors show promising characteristics as they exhibited reproducible and stable responses. The 50 nm thin film had a response of over 10 towards 50 ppb of ozone operating at 50°C, while the 20 nm film had a response of over 22 towards 0.1 ppm of NO<sub>2</sub> at 100°C.