The Expulsion of the Acadians, also known as the Great Upheaval, the Great Expulsion, the Great Deportation, and the Deportation of the Acadians (French: Le Grand Dérangement or Déportation des Acadiens), was the forced removal by the British of the Acadian people from the present-day Canadian Maritime provinces of Nova Scotia, New Brunswick, and Prince Edward Island, and the present-day U.S. state of Maine — parts of an area historically known as Acadia, causing the deaths of thousands of people. The Expulsion (1755–1764) occurred during the French and Indian War (the North American theatre of the Seven Years' War) and was part of the British military campaign against New France. The British first deported Acadians to the Thirteen Colonies, and after 1758, transported additional Acadians to Britain and France. In all, of the 14,100 Acadians in the region, approximately 11,500 were deported, of which at least 5,000 died of disease, starvation or in shipwrecks. Men, women and children were forcibly removed from their homes and their land, which they'd farmed for a century. Their houses were burned and their land given to settlers loyal to Britain, mostly immigrants from New England and then Scotland. The event is largely regarded as a crime against humanity, though contemporary use of the term "genocide" is debated by scholars. A census of 1764 indicates that 2,600 Acadians remained in the colony having eluded capture.In 1710, during the War of the Spanish Succession, the British captured Port Royal, the capital of Acadia, in a siege. The 1713 Treaty of Utrecht, which concluded the larger conflict, ceded the colony to Great Britain while allowing the Acadians to keep their lands. However, the Acadians were reluctant to sign an unconditional oath of allegiance to Britain. Over the following decades, some participated in French military operations against the British and maintained supply lines to the French fortresses of Louisbourg and Fort Beauséjour. As a result, the British sought to eliminate any future military threat posed by the Acadians and to permanently cut the supply lines they provided to Louisbourg by removing them from the area.Without making distinctions between the Acadians who had been neutral and those who had resisted the occupation of Acadia, the British governor Charles Lawrence and the Nova Scotia Council ordered them to be expelled. In the first wave of the expulsion, Acadians were deported to other British North American colonies. During the second wave, they were deported to Britain and France, and from there a significant number migrated to Spanish Louisiana, where "Acadians" eventually became "Cajuns". Acadians fled initially to Francophone colonies such as Canada, the uncolonized northern part of Acadia, Île Saint-Jean (now Prince Edward Island), and Île Royale (now Cape Breton Island). During the second wave of the expulsion, these Acadians were either imprisoned or deported.

Along with the British achieving their military goals of defeating Louisbourg and weakening the Miꞌkmaq and Acadian militias, the result of the Expulsion was the devastation of both a primarily civilian population and the economy of the region. Thousands of Acadians died in the expulsions, mainly from diseases and drowning when ships were lost. On July 11, 1764, the British government passed an order-in-council to permit Acadians to return to British territories in small isolated groups, provided that they take an unqualified oath of allegiance. Today the Acadians live primarily in eastern New Brunswick and in some regions of Prince Edward Island, Nova Scotia, Quebec and Northern Maine. American poet Henry Wadsworth Longfellow memorialized the expulsion in the popular 1847 poem, Evangeline, about the plight of a fictional character, which spread awareness of the expulsion.