An organic light emitting display that defines a plurality of pixels arranged in a matrix form as a plurality of pixel row groups, each of which includes the same number of pixel rows and individually drives the respective pixel row groups. The organic light emitting display includes a display unit including the plurality of pixels, a plurality of data lines, and a plurality of scan lines: a scan driving unit configured to apply scan signals to the plurality of pixels; a data driving unit configured to apply data voltages that are provided to the plurality of pixels to a first output line; and a data distribution unit configured to selectively connect at least two data lines that are continuously arranged to the first output line according to demultiplexing signals. The demultiplexing signals that correspond to the pixel rows included in the respective pixel row groups have different pulse widths.