An image sensor includes; a pixel array including pixels arranged in a first direction and a second direction, wherein the pixels includes a first normal pixel and a first auto focus (AF) pixel adjacent in the first direction, and a second AF pixel and a second normal pixel adjacent in the first direction. Each of the first AF pixel and the second AF pixel includes at least two photodiodes, each of the first normal pixel and the second normal pixel has a quadrangular shape, a first length of the first AF pixel in the first direction is greater than a first length of the first normal pixel in the first direction, and a first length of the second AF pixel in the first direction is greater than a first length of the second normal pixel in the first direction.