Luxembourg (French: Luxembourg [lyksɑ̃buʁ] (About this soundlisten); Dutch: Luxemburg [ˈlyksəmˌbʏrx] (About this soundlisten); German: Luxemburg [ˈlʊksəmbʊʁk] (About this soundlisten); Luxembourgish: Lëtzebuerg; Walloon: Lussimbork), also called Belgian Luxembourg, is the southernmost province of Wallonia and of Belgium. It borders on the country of Luxembourg to the east, the French departments of Ardennes, Meuse and Meurthe-et-Moselle to the south and southwest, and the Walloon provinces of Namur and Liège to the north. Its capital and largest city is Arlon (Luxembourgish: Arel, Dutch: Aarlen), in the south-east of the province.

It has an area of 4,459 km2 (1,722 sq mi), making it the largest Belgian province. With around 285,000 residents, it is also the least populated province, with a density of 64/km2 (170/sq mi), making it a relatively sparsely settled part of a very densely populated region.

It is significantly larger (70%), but much less populous than the neighbouring Grand Duchy of Luxembourg. About eighty percent of the province is part of the densely wooded Ardennes region. The southernmost region of the province is called Gaume or Belgian Lorraine (main city: Virton).

The Arelerland or Arlon region (in red on the map of arrondissements, below) bordering the neighbouring Grand-Duchy of Luxembourg has the particularity that many of its residents have historically spoken Luxembourgish, a language closely related to German, rather than the French or Walloon spoken elsewhere in the province.

The province was separated from the neighbouring Luxembourg by the Third Partition of Luxembourg, de jure in 1830–31 by the Conference of London dealing with the consequences of the Belgian Revolution of 1830, de facto in 1839, after William I, King of the Netherlands and Grand-Duke of Luxembourg, agreed to its decisions and thus the province was given to the newly created Kingdom of Belgium.