Semiconductor devices include a first active pattern including a first lower pattern extending in a first direction and a first sheet pattern spaced apart from the first lower pattern; and a first gate electrode on the first lower pattern, the first gate electrode extending in a second direction and surrounding the first sheet pattern, wherein the first lower pattern includes a first sidewall and a second sidewall opposite to each other, each of the first sidewall of the first lower pattern and the second sidewall of the first lower pattern extends in the first direction, the first gate electrode overlaps the first sidewall of the first lower pattern in the second direction by a first depth, the first gate electrode overlaps the second sidewall of the first lower pattern in the second direction by a second depth, and the first depth is different from the second depth.