A semiconductor device includes a first gate electrode disposed on a substrate and extending in a first horizontal direction, a first gate contact and a dummy gate contact, which are spaced apart from each other in the first horizontal direction and are in contact with a top surface of the first gate electrode, a first interconnect line extending in a second horizontal direction and overlapping the first gate contact in a vertical direction with respect to the upper surface of the substrate, and a voltage generator configured to generate a first voltage and apply the first voltage to the first gate electrode via the first interconnect line and the first gate contact. The first gate electrode receives the first voltage via the first interconnect line and the first gate contact from the voltage generator. The dummy gate contact receives the first voltage via the first gate electrode.