An image sensor includes a semiconductor layer, a plurality of light sensing regions, a first pixel isolation layer, a light shielding layer, and a wiring layer. The semiconductor layer has a first surface and a second surface opposite to the first surface. The plurality of light sensing regions is formed in the semiconductor layer. The first pixel isolation layer is disposed between adjacent light sensing regions from among the plurality of light sensing regions. The first pixel isolation layer is buried in an isolation trench formed between the first surface and the second surface. The light shielding layer is formed on the second surface of the semiconductor layer and on some of the adjacent light sensing regions. The wiring layer is formed on the first surface of the semiconductor layer.