A data driver for providing data voltages to a display panel includes a digital-to-analog converting block, an option storing block, a data swap block and an output buffer block. The digital-to-analog converting block converts line data into the data voltages. The option storing block stores a pixel arrangement option representing a pixel arrangement structure of the display panel. The data swap block is connected to the digital-to-analog converting block and the option storing block, and selectively performs a data swap operation that swaps the data voltages based on the pixel arrangement option and whether the line data are odd line data or even line data. The output buffer block is connected to the data swap block and outputs the data voltages on which the data swap operation is selectively performed to data lines.