This paper reports on the first demonstration of a high frequency (245 MHz) single transistor oscillator based on Graphene-Aluminum Nitride (G-AlN) nano-plate resonator (NPR). For the first time, a 2-dimensional (2D) electrically conductive graphene layer was integrated on top of an ultra-thin (500 nm) AlN nano-plate and excited into a high frequency contour-extensional mode of vibration by piezoelectric transduction. The resulting ultra-thin, low mass and high frequency G-AlN nanomechanical resonator showed high values of electromechanical coupling coefficient (kt2≈1.8%) and quality factor (Qm≈1000) which enabled the implementation of a low phase noise (−87 dBc/Hz @ 1kHz offset and −125 dBc/Hz floor) single transistor oscillator. The experimental results also demonstrate the great potential of the proposed technology for the implementation of a new class of ultra-sensitive and low noise G-AlN resonant sensors.