A semiconductor device includes: an active pattern extending in a first direction on a substrate; a first lower source/drain pattern and a second lower source/drain pattern provided on the active pattern and spaced apart from each other in the first direction; a first upper source/drain pattern provided on the first lower source/drain pattern; a second upper source/drain pattern provided on the second lower source/drain pattern; and a gate electrode crossing the active pattern and extending in a second direction intersecting the first direction. The gate electrode includes an overlapping portion overlapping the active pattern in a third direction perpendicular to the first direction and the second direction. A length of the overlapping portion in the second direction is less than a length of the first lower source/drain pattern in the second direction.