Sweden, formally the Kingdom of Sweden, is a Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, Finland to the east, and is connected to Denmark in the southwest by a bridge–tunnel across the Öresund. At 447,425 square kilometres (172,752 sq mi), Sweden is the largest Nordic country, the third-largest country in the European Union, and the fifth-largest country in Europe. The capital and largest city is Stockholm. Sweden has a total population of 10.5 million, and a low population density of 25.5 inhabitants per square kilometre (66/sq mi), with around 87% of Swedes residing in urban areas, which cover 1.5% of the entire land area, in the central and southern half of the country.

Nature in Sweden is dominated by forests and many lakes, including some of the largest in Europe. Many long rivers run from the Scandes range through the landscape, primarily emptying into the northern tributaries of the Baltic Sea. It has an extensive coastline and most of the population lives near a major body of water. With the country ranging from 55°N to 69°N, the climate of Sweden is diverse due to the length of the country. The usual conditions are mild for the latitudes with a maritime south, continental centre and subarctic north. Snow cover is variable in the densely populated south, but reliable in higher latitudes. Furthermore, the rain shadow of the Scandes results in quite dry winters and sunny summers in much of the country.

Germanic peoples have inhabited Sweden since prehistoric times, emerging into history as the Geats (Swedish: Götar) and Swedes (Svear) and constituting the sea peoples known as the Norsemen. An independent Swedish state emerged during the early 12th century. After the Black Death in the middle of the 14th century killed about a third of the Scandinavian population, the dominance of the Hanseatic League in Northern Europe threatened Scandinavia economically and politically. This led to the formation of the Scandinavian Kalmar Union in 1397, which Sweden left in 1523. When Sweden became involved in the Thirty Years' War on the Protestant side, an expansion of its territories began, forming the Swedish Empire, which remained one of the great powers of Europe until the early 18th century.

Swedish territories outside the Scandinavian Peninsula were gradually lost during the 18th and 19th centuries, ending with the annexation of present-day Finland by Russia in 1809. The last war in which Sweden was directly involved was in 1814 when Norway was militarily forced into a personal union, which peacefully dissolved in 1905. In 2014, Sweden celebrated 200 years of peace, a longer span of peacetime than even Switzerland. Sweden maintained an official policy of neutrality during wartime and non-participation in military alliances during peacetime, although Sweden secretly relied on U.S. nuclear submarines during the Cold War. Sweden has since 2008 joined EU battlegroups, provided intelligence to NATO and since 2009 openly moved towards cooperation with NATO.

Sweden is a highly developed country ranked seventh in the Human Development Index, it is a constitutional monarchy and a parliamentary democracy, with legislative power vested in the 349-member unicameral Riksdag. It is a unitary state, currently divided into 21 counties and 290 municipalities. Sweden maintains a Nordic social welfare system that provides universal health care and tertiary education for its citizens. It has the world's 12th highest GDP per capita and ranks very highly in quality of life, health, education, protection of civil liberties, economic competitiveness, income equality, gender equality and prosperity. Sweden joined the European Union on 1 January 1995 but rejected Eurozone membership following a referendum. It is also a member of the United Nations, the Nordic Council, the Council of Europe, the World Trade Organization and the Organisation for Economic Co-operation and Development (OECD).