An organic light emitting display includes: pixels located at crossing regions between scan lines and data lines; a first control line and a second control line commonly coupled to the pixels; a control line driver configured to supply a first control signal to the first control line for a reset period and to supply a second control signal to the second control line during the reset period and a compensation period. Each pixel includes: an organic light emitting diode; a first transistor configured to control an amount of current supplied from a first power source coupled to a first electrode to a second power source via the organic light emitting diode; a second transistor configured to be turned on when the second control signal is supplied; and a fourth transistor configured to supply an initial voltage to a second electrode of the first transistor when the first control signal is supplied.