Vallby friluftsmuseum, Open-air museum in Västerås, Sweden

Vallby friluftsmuseum is an open-air museum in Västerås with about 40 buildings moved from across Västmanland and rebuilt on the grounds. They include a town quarter around a square, a farmhouse with fourteen buildings, a 1702 manor with a säteri roof, a village school, a country store and Folkets Park with its open-air theatre.

Vallby friluftsmuseum was founded in 1921 by Västmanlands fornminnesförening and curator Sven T. Kjellberg, inspired by Skansen in Stockholm. The plan was to create a "Västmanland in miniature", gathering buildings from across the province and reassembling them on site. The oldest structure dates from the 17th century; the Bergsmansgården farm was built in 1674 by Olof Larsson in Ramsbergs socken and erected at the museum in 1924.

Craft demonstrations take place in several workshops: a pottery, a glass workshop, a silversmith and a printing shop. The Gaggeska gården, named after Rudolf Gagge (1834–1912) who owned it at the end of the 19th century, houses a tavern in the town quarter.

The museum is at Skerikesvägen 2, about two kilometres north of central Västerås and close to the E18. The grounds hold around 40 buildings, so allow time to walk between the town quarter, farm yards and the open-air theatre. The Gaggeska gården in the town quarter houses a värdshus.

The museum's oldest building is Bergsmansgården, also called Spikgården, built in 1674 by the miner Olof Larsson in Ramsberg parish and erected on site in 1924 as a gift from the Swedish state. Its walls and ceilings carry black-and-white floral paintings, among them the wedding at Cana where Jesus turns water into wine.