A display device includes: a first display panel; a second display panel facing the first display panel and including an optical sensor; an electro-optical active layer positioned between the first display panel and the second display panel; and a sensing gate driver including a first sensing gate driver and a second sensing gate driver, the sensing gate driver configured to transmit a sensing gate signal to the optical sensor, in which a first sensing gate off voltage applied to the first sensing gate driver is substantially the same as a second sensing gate off voltage applied to the second sensing gate driver.