Display omitted •ZnSnO3 was fabricated by a microwave-assisted hydrothermal method and calcination.•ZnSnO3 presented a nanocubic and porous structure.•Porous ZnSnO3 nanocubes presented sensitivity and selectivity to triethylamine.•High response and fast response time toward triethylamine detection were attained.•The sensor showed a low detection limit (∼0.6 ppm) to triethylamine detection. Triethylamine (TEA), a volatile organic compound (VOC), is present in several industrial processes and is harmful to human health. Therefore, the development of highly sensitive TEA sensors is desirable. Semiconductor metal oxides (SMOx) have been widely used for VOCs detection due to their efficiency and feasibility. Herein, we report the template-free synthesis of zinc stannate nanocubes (NC-ZnSnO3) by the microwave-assisted hydrothermal method followed by a calcination step. The sample's sensing properties were investigated for different VOCs (methanol, ethanol, isopropanol, acetic acid, acetone, 2-butanone, acetaldehyde, benzene, toluene, m-xylene, and TEA). The sensor presented an improved selectivity toward TEA, showing the highest response of 57.5 to 100 ppm of TEA with a fast response time of 4 s at the optimum operating temperature of 350 °C. The NC-ZnSnO3 also showed a low detection limit for TEA of about 0.6 ppm. In summary, this work described an efficient method for producing NC-ZnSnO3 and demonstrated that this material has high selectivity and sensitivity for TEA detection.