Nykvarn is a locality situated in Stockholm County, Sweden. It serves as the seat of Nykvarn Municipality, which had a population of 7,560 inhabitants as of 2017. Historically, the area was part of Södertälje Municipality between 1971 and 1998.
The city is known for its local music scene, serving as the hometown for several bands including Hyena Breed, Feed Filiph, From Zero to Hero, and Aldiureep. Additionally, it is the birthplace of Stanley Cup winner Carl Hagelin. The locality also hosts the annual Moshpit Open Festival, a rock and metal event.