An organic light emitting display apparatus includes a first data line, a comparator, and a data generator. The first data line is connected to a first pixel. The comparator compares first image data of input image data to at least one of a first critical grayscale value or a second critical grayscale value, where the first image data corresponds to the first pixel. The data generator determines the first critical grayscale value or the second critical grayscale value as first corrected image data when the first image data is equal to or greater than the first critical grayscale value but lower than the second critical grayscale value.