The municipality (originally the parish) is named after the old Ullensaker farm (Old Norse: Ullinshof), since the first church was built there. The first element is the genitive case of the name Ullinn (a sideform of Ullr). The last element was originally hof which means "temple" but this was later (around 1500 AD) changed to aker meaning "acre" or "field".
Ullensaker does not have an heraldic coat-of-arms properly granted. The municipality uses a non-heraldic badge that is from modern times. The logo was adopted on 8 November 1979, and it shows the god Ullr of Norse mythology holding a bow and three arrows. The colors on the logo can vary.
Number of minorities (1st and 2nd generation) in Ullensaker by country of origin in 2015
Ullensaker has had a huge population increase the last 50 years. This increase has been slightly accelerating the last few years. From the year 2000 to 2007, the population of Ullensaker increased by almost 6,000 people. The recent increase is partly attributed to the founding of Oslo Airport, Gardermoen.