An organic light emitting display includes pixels coupled to scan lines, first control lines, second control lines, data lines, and first and second power sources. The organic light emitting display further includes a control line driver for providing a first control signal and a second control signal to the pixels through the first control lines and the second control lines, a scan driver for providing scan signals to the pixels through the scan lines, and a data driver for providing data signals to the pixels through data lines. The control line driver simultaneously supplies a first off control signal to the pixels through the first control lines in a first period, simultaneously supplies a reference voltage to the pixels through the first control lines in a second period, and simultaneously supplies a first on control signal to the pixels through the first control lines in a third period.