A display device includes: a substrate; a gate line, a dummy gate line, a data line, a dummy data line, a pixel electrode, and a dummy pixel electrode, each disposed on the substrate; a switching element connected to the gate line, the data line, and the pixel electrode; a dummy switching element connected to the dummy gate line, the dummy data line, and the dummy pixel electrode; a compensation circuit detecting a change amount of a drain current based on drain currents generated from the dummy pixel at different time points, and detecting a change amount of a gate voltage of the dummy switching element based on the change amount of the drain current; a power supply circuit outputting a corrected gate-off voltage based on the change amount of the gate voltage; and a gate driver applying the corrected gate-off voltage to the gate line.