A display device comprises a display panel and a timing controller. Electrical characteristics of sensing target display lines of the display panel are sensed during the sensing periods of vertical active periods of sensing drive frames. Data lines are driven with data signals without sensing the display lines during the vertical active periods of normal drive frames and during display periods of the vertical active periods of the sensing drive frames. A timing controller supplies timing signals to a gate driver as a plurality of clock pulses to control timing of the gate driver providing gate pulses to the gate lines. The clock pulses have a first timing during the vertical active periods of the sensing drive frames and the clock pulses have a second timing during the vertical active periods of the normal drive frames in which the second timing is different than the first timing.