An image sensor is provided. The image sensor includes, a substrate including a light-receiving region and a pad region disposed around the light-receiving region, wherein the light-receiving region receives light to generate image data, a photoelectric conversion layer disposed on the light-receiving region of the substrate, an anti-reflection layer disposed on the photoelectric conversion layer and including a plurality of subsidiary anti-reflection layers, a microlens disposed on the anti-reflection layer, a delamination-preventing layer disposed on the pad region of the substrate, and a wiring layer disposed on the delamination-preventing layer, wherein a lowermost one of the subsidiary anti-reflection layers of the anti-reflection layer includes a first material composition and the delamination-preventing layer includes a second material composition different from the first material composition.