Langangen is a village in Porsgrunn Municipality in Telemark county, Norway. The village is located in the far eastern part of the municipality, just before the border with neighboring Larvik Municipality, about 10 km to the southeast of the town of Porsgrunn. Langangen has its own elementary school and Langangen Church. The 0.43 km2 village has a population (2022) of 465 and a population density of 1074 PD/km2. The European route E18 highway historically passed through the middle of the village, but in 1979 the road was re-routed over a new Langangen bridge further to the north.