An organic light-emitting display device can include an organic light-emitting element; a driving transistor connected in series with the organic light-emitting element, the driving transistor and the organic light-emitting element being between a first driving power supply line for supplying a first driving voltage and a second driving power supply line for supplying a second driving voltage lower than first driving voltage; a first transistor configured to turn on based on an i-th scan signal and supply a data voltage to a first node, where i is a natural number greater than or equal to 2 and less than or equal to N, and N is a number of scan-lines; a capacitor between the first node and a gate electrode of the driving transistor, the capacitor is configured to supply a turn-on signal of the driving transistor to the gate electrode of the driving transistor based on the data voltage; and a second transistor configured to turn on based on a (i−1)-th scan signal and supply a first reference voltage to a second node, in which the second node is disposed between the driving transistor and the capacitor, and the capacitor is between the first and second nodes.