Brussels, officially the Brussels-Capital Region, is a region of Belgium comprising 19 municipalities, including the City of Brussels, which serves as the national capital. Located in the central portion of the country, it forms an enclave within the Flemish Region and lies less than 4 km south of the Walloon Region. The area is part of both the French Community of Belgium and the Flemish Community, functioning as a distinct administrative entity separate from the surrounding regions.

The settlement grew from a small rural community on the river Senne into an important city-region. Official founding is usually dated to around 979, when Charles, Duke of Lower Lorraine, transferred relics to a chapel and ordered the first permanent fortification. Historically Dutch-speaking, the area underwent a language shift to French from the late 19th century. Since its creation in 1989, the region has been officially bilingual in French and Dutch.

The city blends medieval Flemish heritage with grandiose projects from its time as a capital of a French-speaking country and modern architecture housing international institutions. Only a small historic centre was preserved after old town parts were destroyed for new ministries and barracks between 1880 and 1980. Principal attractions include the historic Grand-Place/Grote Markt, Manneken Pis, the Atomium, and cultural institutions such as La Monnaie/De Munt and the Museums of Art and History.

Brussels is known for its cuisine, including local waffles, chocolate, French fries, and numerous beer types, as well as its long tradition of Belgian comics, earning it the title of a comic strip capital. It is also hailed as a capital of the European Union due to hosting principal EU institutions, NATO headquarters, and the Benelux secretariat. Its name is sometimes used metonymically to describe the EU and its institutions.

The region covers 162 km2 and has a population of 1,255,795 as of 2025. It is Belgium's most densely populated region and its economic capital, classified as an Alpha global city with Euronext Brussels. The Brussels Metro is the only rapid transit system in the country, while its airport and railway stations are the largest and busiest. The city features an oceanic climate with moderately cold, wet winters and warm summers.