A scan driver and a display device including the same. The scan driver includes a plurality of shift registers including an input signal terminal into which an initial signal or an output signal of a previous stage is inputted, two clock signal terminals to which 2 phase clock signals are transferred, two control signal terminals to which a first control signal and a second control signal controlling a driving mode of simultaneously driving or sequentially driving output signals of all stages are transferred, and output signals terminals from which the output signals are outputted, wherein in the sequential driving mode, the first control signal and the second control signal are transferred as a predetermined first level voltage and in the simultaneous driving mode, the first control signal and the second control signal are transferred alternately as the first level voltage and a predetermined second level voltage.