An image sensor includes a first structure and a second structure stacked on the first structure in a vertical direction, the first structure including first and second pixel pads electrically connected to first and second floating diffusion regions, respectively, and a first coupling suppression line penetrating between the first and second pixel pads, and electrically connected to the first ground structure, and the second structure including third and fourth pixel pads electrically connected to first and second source-follower gates, respectively; and a second coupling suppression line penetrating between the third and fourth pixel pads, and electrically connected to the second ground structure.