An image sensor includes a substrate having first and second surfaces and first and second regions. Unit pixels including photoelectric conversion layers are arranged inside the first region. A pixel separation pattern extends from the first surface to the second surface in the first region, separates each of the unit pixels, and includes a pixel separation spacer film and a pixel separation filling film. A dummy pixel separation pattern extends from the first surface to the second surface in the second region, and includes a dummy pixel separation filling film. A wiring structure disposed on the second surface includes an inter-wiring insulating film and a first wiring. A first contact directly connects the dummy pixel separation filling film and connects the dummy pixel separation filling film to the first wiring. A height of the pixel separation filling film is greater than a height of the dummy pixel separation filling film.