There is provided an organic light emitting display capable of improving the display quality of a low brightness region. The organic light emitting display includes pixels positioned at intersections of scan lines, emission control lines, and data lines, a converter for receiving data to generate brightness values, a timing controller for extracting emission time values and gamma values to correspond to the brightness values, an emission control line driver for supplying emission control signals to the emission control lines so that emission times of the pixels are controlled to correspond to the emission time values, and a gamma voltage generator for generating gamma voltages corresponding to the gamma values.