A 3D display device is provided. The 3D display device includes a display panel and a liquid crystal lens panel. The display panel operates in one of a 2D mode for displaying a 2D image, a 3D mode for displaying a 3D image, and a coincident mode for displaying the 2D image and the 3D image. The liquid crystal lens panel is disposed on the display panel. The liquid crystal lens panel is configured to refract the 3D image through a third region of the liquid crystal lens panel and to transmit the 2D image without refracting the 2D image when the display panel operates in the coincident mode.