A semiconductor device includes a stack structure including interlayer insulating layers and horizontal layers on a lower structure; a memory vertical structure vertically penetrating the stack structure; first and second barrier structures penetrating the stack structure in parallel; a supporter pattern penetrating the stack structure; and through contact plugs penetrating the stack structure. The first barrier structure includes first barrier patterns arranged in a first direction and spaced apart from each other, and second barrier patterns arranged in the first direction and spaced apart from each other. Each of the first and second barrier patterns includes a linear shape extending in the first direction. In a first barrier pattern and a second barrier pattern adjacent to each other, a portion of the first barrier pattern opposes a portion of the second barrier pattern in a second direction perpendicular to the first direction.