A display device includes a sub-pixel comprising a light emitting device and a driving transistor DRT electrically connected to a first electrode of the light emitting device and configured to drive the light emitting device, and a reference voltage line electrically connected to the sub-pixel SP and applying an initialization voltage to the first electrode of the light emitting device, wherein a voltage level of the initialization voltage is changed according to a length of a blank period, thereby improving display quality of the image at a low refresh rate in a variable refresh rate mode.