Enhancing the reliability and sensitivity of gas sensors based on FETs has been of extensive concern for their practical application. However, few reports are available on nanofiber FET gas sensors fabricated by the electrospinning process. In this work, ethanol gas sensors based on Yb-doped In2O3 (InYbO) nanofiber FETs are fabricated by a simple and fast electrospinning method. The optimized In2O3 nanofiber FETs with a doping concentration of 4 mol % show a better electrical performance, including a high mobility of 6.67 cm(2)/Vs, an acceptable threshold voltage of 3.27 V, and a suitable on/off current ratio of 10(7), especially the enhanced bias-stress stability. When employed in ethanol gas sensors, the gas sensors exhibit enhanced stability and improved sensitivity with a high response of 40-10 ppm, which is remarkably higher than that of previously reported ethanol gas sensors. Moreover, the InYbO nanofiber FET sensors also demonstrate a low limit of detection of 1 ppm and improved sensing performance ranging from sensitivity to the ability of selectivity. This work opens up a new prospect to achieve highly sensitive, selective, and reliable ethanol gas sensors using electrospun Yb-In2O3 nanofiber FETs with improved stability.