In the present work, comparative investigations on NO₂ gas sensing properties of the hybrid nanocomposite thin films of polyaniline (PANI), ZnO and PANI–ZnO towards NO₂ gas at room temperature have been reported. The effect of concentration of PANI in the composite thin films on NO₂ gas sensing has been investigated. Structural and surface morphological characterizations have been carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The presence of 5 wt% PANI in the composite films was found to give a maximum sensing response of ∼6.11 × 10² towards 20 ppm NO₂ gas having fast response and recovery time of about 2.16 min and 3.5 min respectively.