A display device includes a display panel including a pixel circuit, a display panel driving circuit that drives the display panel, a voltage generating circuit that receives an input power supply voltage when the display device is powered on and generates display panel voltages and driving circuit voltages based on the input power supply voltage, and an over-current protecting circuit that monitors an over-current generated inside the display device and generates a shut-down request signal when the over-current is detected. The voltage generating circuit outputs an initialization voltage at a first time point corresponding to a time point at which the input power supply voltage is received. The display panel driving circuit outputs a scan clock signal at a second time point. The over-current protecting circuit performs a first over-current protecting operation in a power-on monitoring period set between the first time point and the second time point.