The population of Belgium is 10,258,762 (2001 estimate). Nearly 60 percent live in the Flanders region. The overall population density, one of the highest in Europe, is 336 persons per sq km (870 per sq mi). The largest concentrations were in the Brussels, Antwerp, Liège, and Ghent (Gent) industrial areas, as well as in the narrow industrial region between Mons and Charleroi. In recent decades the Limbourg city region has increased in population because of industrial expansion in that area. Almost 10 percent of all Belgians live in Brussels, which is also home to vast numbers of foreign guest workers. Some 97 percent of the population is classified as urban.

The population of Belgium is divided into three linguistic communities. In the north the Flemings, who constitute more than half of Belgium's population, speak Netherlandic. Although speakers of English usually call the Netherlandic spoken in The Netherlands “Dutch” and that spoken in Belgium “Flemish,” both are actually the same language . In the south the French-speaking Walloons make up about one-third of the country's population. About one-tenth of the population is completely bilingual, but a majority have some knowledge of both French and Flemish. The German-language region in eastern Liège province, containing fewer than 1 percent of the Belgians, consists of 9 communes around Eupen and Saint-Vith. The city of Brussels comprises 19 officially bilingual communes, although the metropolitan area extends far into the surrounding Flemish and Walloon communes. The French-speaking population is by far the larger in the capital region