An image sensor may include a substrate having a photoelectric conversion element and a grid pattern formed over the substrate and having a flat upper surface, a first side surface, and a second side surface, wherein the first side surface and the second side are located opposite to each other. A first internal angle is formed between the flat upper surface and the first side surface, a second internal angle is formed between the flat upper surface and the second side surface, and the first internal angle may be smaller than the second internal angle.