This paper reports a novel nanoelectromechanical oscillator by using a single semiconducting zinc oxide (ZnO) nanowire that is suspended across on two micromachined metal electrodes. The oscillator is electrostatic-driven into a motion that is self-detected based on a field effect transistor (FET) principle and a lock-in detection method. A continuum electromechanical model is established to realize a theoretical analysis on the oscillator. The primary experimental measurements on the devices are performed. The experimental results show that the oscillator is with a resonant frequency of tens of MHz and two resonance peaks of the current response at double frequency points are observed. The current response of the oscillator can be adjusted through tuning AC and DC gate and source–drain voltages. Compared with other reported nanoelectromechanical oscillators, our oscillator based on a single ZnO nanowire is provided with an enhanced electromechanical performance. The merits significantly enhance the device's practicability. The device can be potentially applied for actuators and sensors.