A gate driver and an organic light emitting diode (OLED) display including the gate driver are disclosed. The gate driver includes a shift register block including a plurality of cascade-connected shift registers, a selection block including a plurality of selection units, which are respectively connected to the plurality of shift registers, and a buffer block including a plurality of buffers, which are respectively connected to the plurality of selection units. Each of the shift registers outputs a scan pulse, whose a phase is shifted by one horizontal period, in response to a start voltage, a first clock, a second clock, and a third clock.