To provide a touch sensor including a transistor and a capacitor in which the transistor and the capacitor are electrically connected to each other, the capacitor includes a pair of electrodes and a dielectric layer, the dielectric layer is located between the pair of electrodes, and one of the pair of electrodes includes an oxide conductor layer. To provide a touch panel including the touch sensor, a light-blocking layer, and a display element in which the touch sensor is located more on the display surface side of the touch panel than on the display element side, the light-blocking layer is located more on the display surface side than on the touch sensor side, the display element includes a portion overlapping with the capacitor, and the light-blocking layer includes a portion overlapping with the transistor.