A semiconductor device includes a first active pattern on a substrate. The first active pattern includes a pair of first source/drain patterns and a first channel pattern therebetween. A gate electrode is disposed on the first channel pattern, and a first gate spacer is disposed on a side surface of the gate electrode. The first gate spacer includes a first spacer and a second spacer. A top surface of the first spacer is lower than a top surface of the second spacer. A first blocking pattern is disposed on the first spacer, and a gate contact is coupled to the gate electrode. The first blocking pattern is interposed between the gate contact and the second spacer.