An image sensor that provides a uniform sensitivity for pixels having color filters of the same color to increase the image quality is provided. The image sensor includes a substrate, a first grid pattern disposed on the substrate and including a first side wall and a second side wall opposite to the first side wall, a first pixel including a first photoelectric conversion element and a first color filter, and a second pixel including a second photoelectric conversion element and a second color filter. The first color filter contacts the first side wall and the second color filter contacts the second side wall. The first color filter and the second color filter are color filters of same color, and a first thickness of the first color filter is greater than a second thickness of the second color filter.