An image sensor is provided. The image sensor includes a semiconductor substrate including a first surface and a second surface opposite to each other. A semiconductor pattern is disposed on the first surface of the semiconductor substrate and it extends in a first direction perpendicular to the first surface. A buried transmission gate electrode is disposed in a transmission gate trench extending from the first surface of the semiconductor substrate to an interior of the semiconductor substrate. A first gate electrode at least partially surrounds a side wall of the semiconductor pattern and has a ring-shaped horizontal cross-section. A color filter is disposed on the second surface of the semiconductor substrate.