The Kingdom of Great Britain was a sovereign state in Western Europe from 1707 to the end of 1800. The state was created by the 1706 Treaty of Union and ratified by the Acts of Union 1707, which united the Kingdom of England (including Wales) and the Kingdom of Scotland to form a single kingdom encompassing the whole island of Great Britain and its outlying islands, with the exception of the Isle of Man and the Channel Islands. The unitary state was governed by a single parliament at the Palace of Westminster, but distinct legal systems—English law and Scots law—remained in use, as did distinct educational systems and religious institutions, namely the Church of England and the Church of Scotland remaining as the national churches of England and Scotland respectively.

The formerly separate kingdoms had been in personal union since the Union of the Crowns in 1603 when James VI of Scotland became King of England and King of Ireland. Since James's reign, who had been the first to refer to himself as "king of Great Britain", a political union between the two mainland British kingdoms had been repeatedly attempted and aborted by both the Parliament of England and the Parliament of Scotland. Queen Anne (r. 1702–1714) did not produce a clear Protestant heir and endangered the line of succession, with the laws of succession differing in the two kingdoms and threatening a return to the throne of Scotland of the Roman Catholic House of Stuart, exiled in the Glorious Revolution of 1688.

The resulting kingdom was in legislative and personal union with the Kingdom of Ireland from its inception, but the Parliament of Great Britain resisted early attempts to incorporate Ireland in the political union. The early years of the newly united kingdom were marked by Jacobite risings, particularly the Jacobite rising of 1715. The relative incapacity or ineptitude of the Hanoverian kings resulted in a growth in the powers of Parliament and a new role, that of "prime minister", emerged in the heyday of Robert Walpole. The "South Sea Bubble" economic crisis was brought on by the failure of the South Sea Company, an early joint-stock company. The campaigns of Jacobitism ended in defeat for the Stuarts' cause in 1746.

The Hanoverian line of monarchs gave their names to the Georgian era and the term "Georgian" is typically used in the contexts of social and political history for Georgian architecture. The term "Augustan literature" is often used for Augustan drama, Augustan poetry and Augustan prose in the period 1700–1740s. The term "Augustan" refers to the acknowledgement of the influence of classical Latin from the ancient Roman Empire.

Victory in the Seven Years' War led to the dominance of the British Empire, which was to become the foremost global power for over a century. Great Britain dominated the Indian subcontinent through the trading and military expansion of the East India Company in colonial India. In wars against France, it gained control of both Upper and Lower Canada, and until suffering defeat in the American War of Independence, it also had dominion over the Thirteen Colonies. From 1787, Britain began the colonisation of New South Wales with the departure of the First Fleet in the process of penal transportation to Australia. Britain was a leading belligerent in the French Revolutionary Wars.

Great Britain was merged into the United Kingdom of Great Britain and Ireland on 1 January 1801, with the Acts of Union 1800, enacted by Great Britain and Ireland, under George III, to merge with it the Kingdom of Ireland.

The name Britain descends from the Latin name for the island of Great Britain, Britannia or Brittānia, the land of the Britons via the Old French Bretaigne (whence also Modern French Bretagne) and Middle English Bretayne, Breteyne. The term Great Britain was first used officially in 1474.

The use of the word "Great" before "Britain" originates in the French language, which uses Bretagne for both Britain and Brittany. French therefore distinguishes between the two by calling Britain la Grande Bretagne, a distinction which was transferred into English.