A semiconductor memory device may include at least one semiconductor pattern including a horizontal portion extending in a second direction parallel to a top surface of a semiconductor substrate and a vertical portion extending in the first direction, at least one gate electrode on the horizontal portion of the at least one semiconductor pattern and extending in a third direction different from the first direction and the second direction, and at least one information storage element connected to the vertical portion of the at least one semiconductor pattern, wherein a thickness of the horizontal portion of the at least one semiconductor pattern in the first direction is smaller than a thickness of the vertical portion of the at least one semiconductor pattern in the first direction.