A display device including: a display panel including scan write lines, sensing lines, pixels respectively connected to the scan write lines, and optical sensors respectively connected to the scan write lines and the sensing lines; a scan driver configured to sequentially output scan write signals to the scan write lines in response to a scan control signal; a read-out circuit configured to receive light sensing signals of the optical sensors from the sensing lines in response to a first sampling signal; and a timing controller configured to control the scan driver and the read-out circuit, wherein an interval between pulses of the first sampling signal has a first horizontal period, and an interval between pulses of each of the scan write signals has a second horizontal period.