An organic light emitting display device including a display panel including a plurality of scan lines, first through (M)th data lines crossing the scan lines, and a plurality of pixels, where M is an integer greater than 1, a scan driver configured to provide scan signals to the pixels through the plurality of scan lines, a data driver configured to provide data signals to the pixels through the first through (M)th data lines, and a porch data generator configured to generate porch data based on an average value of at least a portion of frame data, and to provide the porch data to the data driver, wherein the data driver is configured to generate the data signals based on the porch data during a porch period, and to generate the data signals based on the frame data during an active period.