Wellen (Dutch pronunciation: ['ʋɛlə(n)] ^ⓘ; Limburgish: Wille) is a municipality located in the Belgian province of Limburg. On 1 January 2024, Wellen had a total population of 7,490. The total area is 26.72 km² with a population density of 279 inhabitants per km².

The municipality consists of the following sub-municipalities: Wellen, Berlingen, Herten and Ulbeek. Other population centres and hamlets include: Bos, Beurs, Kukkelberg, Langenakker, Oetersloven, Overbroek, Russelt, and Vrolingen.

Archaeological findings suggest the place was inhabited already during the Frankish period (5th to 7th century). Debris from the river Herk on that spot made the soil fertile for farming. However, any mention of the name Wellene or Welnis doesn't occur until the second half of the 12th century.

The name Wellen derives from the Middle Dutch "wellene", meaning "source" or "pit" or, alternately, from Latin terra Villina, "agricultural holding". Wellen was long associated with the abbey of Munsterbilzen, founded around 670.