Semiconductor devices are provided. The semiconductor device includes an active fin which extends along a first direction and has a protruding shape, a gate structure which is disposed on the active fin to extend along a second direction intersecting the first direction, and a spacer which is disposed on at least one side of the gate structure, wherein the gate structure includes a first area and a second area which is adjacent to the first area in the second direction, wherein a first width of the first area in the first direction is different from a second width of the second area in the first direction, and the spacer extends continuously along both the first area and the second area.