Here, we studied the gas sensing response properties for acetone and formaldehyde by a chemiresistive nanocube In₂O₃@RGO heterostructure sensor. The nanocube In₂O₃@RGO heterostructure based sensor demonstrates a high response to acetone (∼85%) and formaldehyde (∼88%) at 25 ppm concentration and optimum working temperatures of 175 °C and 225 °C, respectively. Additionally, we examined the influence of potential barrier heights in the response/recovery time of the nanocube In₂O₃@RGO heterostructure based acetone and formaldehyde gas sensor. The real-time response/recovery analysis reveal that the sensor response depends on the potential barrier height as well as adsorbed active sites (O₂⁻ & O⁻) on the sensor surface. Furthermore, the nanocube In₂O₃@RGO heterostructure based gas sensor shows good selectivity to acetone and formaldehyde at optimum working temperature of 175 °C and 225 °C, respectively, compared to the other interfering gases such as ethanol, methanol, chloroform, toluene, benzene, ammonia, formic acid and acetic acid. The life-time analysis has been performed for 30 days, which showes the stability of nanocube In₂O₃@RGO heterostructure based acetone and formaldehyde sensor.