Luxembourg ( (listen) LUK-səm-burg; Luxembourgish: Lëtzebuerg [ˈlətsəbuəɕ] (listen); French: Luxembourg [lyksɑ̃buʁ]; German: Luxemburg [ˈlʊksm̩bʊʁk]), officially the Grand Duchy of Luxembourg, is a small landlocked country in Western Europe. It borders Belgium to the west and north, Germany to the east, and France to the south. Its capital and most populous city, Luxembourg, is one of the four institutional seats of the European Union (together with Brussels, Frankfurt, and Strasbourg) and the seat of several EU institutions, notably the Court of Justice of the European Union, the highest judicial authority. Luxembourg's culture, people, and languages are highly intertwined with its French and German neighbors; while Luxembourgish is the only national language of the Luxembourgish people, French is the only language for legislation, and all three – Luxembourgish, French and German – are considered official languages and are used for administrative matters in the country.

With an area of 2,586 square kilometers (998 sq mi), Luxembourg is one of the smallest countries in Europe. In 2022, it had a population of 645,397, which makes it one of the least-populated countries in Europe, albeit with the highest population growth rate; foreigners account for nearly half the population. Luxembourg is a representative democracy headed by a constitutional monarch, Grand Duke Henri, making it the world's only remaining sovereign grand duchy.

Luxembourg is a developed country with an advanced economy and one of the world's highest GDP (PPP) per capita - the highest under IMF and World Bank estimates. The city of Luxembourg was declared a UNESCO World Heritage Site in 1994 due to the exceptional preservation of its vast fortifications and historic quarters. Luxembourg is a founding member of the European Union, OECD, the United Nations, NATO, and the Benelux. It served on the United Nations Security Council for the first time in 2013 and 2014.