The Benelux Union or Benelux is a politico-economic union and formal international intergovernmental cooperation of three neighbouring states in western Europe: Belgium, the Netherlands, and Luxembourg. The name is a Blend word formed from joining the first few letters of each country's name and was first used to name the customs agreement that initiated the union. It is now used more generally to refer to the geographic, economic, and cultural grouping of the three countries.

Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to the south, and the North Sea to the west. It covers an area of 30,689 km2 (11,849 sq mi) and has a population of more than 11.5 million, making it the 22nd most densely populated country in the world and the 6th most densely populated country in Europe, with a density of 376/km2 (970/sq mi). Belgium is part of an area known as the Low Countries, historically a somewhat larger region than the Benelux group of states, as it also included parts of northern France. The capital and largest metropolitan region is Brussels; other major cities are Antwerp, Ghent, Charleroi, Liège, Bruges, Namur, and Leuven.