A display device having a photosensing function is provided. A display device having a biometric authentication function typified by fingerprint authentication is provided. A display device having both a touch panel function and a biometric authentication function is provided. The display device includes a first substrate, a light guide plate, a first light-emitting element, a second light-emitting element, and a light-receiving element. The first substrate and the light guide plate are provided to face each other. The first light-emitting element and the light-receiving element are provided between the first substrate and the light guide plate. The first light-emitting element has a function of emitting first light through the light guide plate. The second light-emitting element has a function of emitting second light to a side surface of the light guide plate. The light-receiving element has a function of receiving the second light and converting the second light into an electric signal. The first light includes visible light, and the second light includes infrared light.