Highly selective oxidizing gas sensors are of great importance for environmental pollution monitoring. In this work, a hybrid material containing Zn₂SnO₄nanoparticles (NPs) and immobilized reduced graphene oxide (Zn₂SnO₄-RGO) was developed as a high performance gas sensing material for the detection of ppb-levels of oxidizing gases (NO₂ and O₃). The structural, morphological and compositional properties of the Zn₂SnO₄-RGO hybrids were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), which demonstrated the successful anchoring of Zn₂SnO₄ NPs on RGO nanosheets. The obtained Zn₂SnO₄-RGO hybrids exhibited outstanding sensing performance for detecting oxidizing gases (NO₂ and O₃) with very low cross sensitivities to reducing gases, such as C₂H₅OH, CH₃COCH₃ and CO. The Zn₂SnO₄-RGO based sensors exhibited high response values of up to 3.50 for 500 ppb NO₂, which is higher than that for detection of 500 ppb O₃ (1.78) at 30 °C under 50% relative humidity (RH). Moreover, the NO₂sensing performances of Zn₂SnO₄-RGO-based sensors were investigated under various RH. In all cases, the sensors based on RGO and Zn₂SnO₄-RGO hybrids presented p-type behavior. The sensors based on Zn₂SnO₄-RGO hybrids also exhibited high response values of up to 3.62 for 1 ppm NO₂ at 50 °C in 80% RH, which is much higher than that of pure RGO (1.31). The excellent sensing performances are mainly ascribed to the synergetic effect of Zn₂SnO₄ NPs and RGO. Furthermore, the surface reaction between Zn₂SnO₄-RGO hybrids and NO₂can be concluded from Operando diffuse reflectance infrared Fourier transformed spectroscopy (Operando DRIFT).