Sem is a village in Skien Municipality, in Telemark, Norway. Sem lies at 105 m above sea level, in the Scandinavian mountains. The nearest city is Porsgrunn/Skien, 10.7 km to the south. Among the landmarks around are Gjerpen Church (1.8 km), Skien Church (3.0 km) and Gimsøy Abbey (4.0 km). Among the natural features are Stubbekollen (14.5 km) and Geiteryggen (5.6 km).