A device for mapping a color gamut includes a color gamut determinator and a color gamut mapper. The color gamut determinator determines an output color gamut using a gain value corresponding to information of a first color gamut, information of a second color gamut and a control condition. The color gamut mapper converts the color gamut of an input image data into the output color gamut. Accordingly, it is possible to provide a device and method for mapping a color gamut, which can determine an optimal color gamut corresponding to a change in control condition, and accordingly improve color accuracy and color reproducibility.