Image sensors are provided. An image sensor includes a semiconductor substrate including a pixel region and an optical black region. The image sensor includes a plurality of photoelectric conversion regions in the pixel region. The image sensor includes a wiring structure on a first surface of the semiconductor substrate. The image sensor includes a light shielding layer on a second surface of the semiconductor substrate in the optical black region. Moreover, the image sensor includes a light shielding wall structure that is in the semiconductor substrate between the pixel region and the optical black region and that is connected to the light shielding layer.