A scan driver includes: a plurality of scan driving blocks including an output terminal outputting a scan signal to a scan line; a first transistor transmitting a voltage of a power source to the output terminal; a second transistor transmitting a clock signal to the output terminal; and a third transistor including a gate electrode connected to a node formed with a gate-on voltage turning on the second transistor, one terminal connected to the power source, and the other terminal connected to the gate electrode of the first transistor. The scan driver may reduce the influence of a leakage current even though application of the scan signal is increased, and a scan signal of a uniform voltage level may be output.