The 2010 G-20 Toronto summit was the fourth meeting of the G-20 heads of government, in discussion of the global financial system and the world economy, which took place at the Metro Toronto Convention Centre in Toronto, Ontario, Canada, during June 26–27, 2010. The summit's priorities included evaluating the progress of financial reform, developing sustainable stimulus measures, debating global bank tax, and promoting open markets. Alongside the twenty-one representatives of the G-20 major economies, leaders of six invited nations, and eight additional intergovernmental organizations also took part in the summit.

Prior to the summit, Canadian prime minister Stephen Harper announced that the theme would be "recovery and new beginnings," referring to an anticipated economic stimulus from the impact of the ongoing world recession. Harper initially proposed to hold the summit in the town of Huntsville, Ontario, where the 36th G8 summit was scheduled immediately prior. Organizers later deemed the town insufficient to provide hospitality for the large number of G-20 delegates and journalists and the venue was changed to Toronto.

Toronto (/təˈrɒntoʊ/, colloquially /ˈtrɒnoʊ/) is the largest city in Canada and the provincial capital of Ontario. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from the Mississaugas of the New Credit. The settlement was later established as the Town of York and proclaimed as the new capital of Upper Canada by its lieutenant-governor, John Graves Simcoe. In 1834, York was incorporated as a city and renamed to its present name. The city was ransacked in the Battle of York during the War of 1812 and damaged in two great fires in 1849 and in 1904. Since its incorporation, Toronto has repeatedly expanded its borders through amalgamation with surrounding municipalities, most recently in 1998.

With over 2.6 million residents, it is the fifth most populous city in North America. Its metropolitan area has over 5.5 million residents. Toronto is at the heart of the Greater Toronto Area (GTA), and is part of a densely populated region in Southern Ontario known as the Golden Horseshoe, which has a population of nearly 9 million people as of 2011. The census metropolitan area (CMA) had a population of 5,583,064, and the Greater Toronto Area had a population of 6,054,191 in the 2011 Census. Its cosmopolitan and international population reflects its role as an important destination for immigrants to Canada. Toronto is one of the world's most diverse cities by percentage of non-native-born residents, with about 49% of the population born outside Canada. Toronto is also consistently rated as one of the world's most livable cities by the Economist Intelligence Unit and the Mercer Quality of Living Survey.