A flexible display device includes a flexible display panel that includes a display region, a gamma data storage that stores entire driving gamma data generated by a first multi-time programming for an entirety of the display region, and partial driving gamma data generated by a second multi-time programming for a portion of the display region, a gamma reference voltage generator that generates a gamma reference voltage based on the entire driving gamma data when the flexible display panel is not deformed, and generates the gamma reference voltage based on the partial driving gamma data when the flexible display panel is deformed, and a data driver that provides data voltages to the flexible display panel based on the gamma reference voltage.