Upplands Väsby Municipality (Upplands Väsby kommun) is a municipality in Stockholm County in east central Sweden, with a population of 38,963 (2010). Its seat is located in the town of Upplands Väsby.
The municipality was created in connection with the municipal reform of 1952, when the rural municipalities Ed, Fresta and Hammarby were amalgamated. It got its name from a settlement which had evolved around the railway station.
The name Väsby can be attested (as Vesby) from the 13th century. The prefix "Upplands" came to be used by the post station in 1919 as a means of separating it from other Väsbys in the country. The municipality was then named "Upplands-Väsby" for a time, but the dash has now been removed.
Upplands Väsby is located in between Stockholm and the large airport Arlanda, and the main line railroad goes through the municipality. It is now an important link to the new "Upptåget", enabling change between "Upptåget", a new train service going north to Arlanda, Uppsala, and all the way to Gävle, and Stockholm commuter rail.
Located in the province of Uppland the municipality holds remains from the Stone Age. Runestones and axes from the Bronze Age have also been found. The number of rune inscriptions in the municipality amounts to 76.
When Väsby Centrum, a shopping centre that currently houses some 60 stores, was built in Väsby in 1972 the population grew markedly. The mall is currently undergoing a large increase; 20 new stores will have opened by spring 2007, bringing the mall's total up to 80 stores.