The original flag of Toronto was designed by Rene De Santis, a 21-year-old George Brown College student, and won in a 1974 competition held by the City of Toronto Flag Design Committee. After the city amalgamated in 1997, the City Council looked for new designs from the public, but did not approve of any. De Santis suggested minor modifications to the original flag, which was adopted in October 1999, to create the current flag. The flag displays the twin towers of the Toronto City Hall on a blue background, with the red maple leaf of the Flag of Canada at its base, representing the Council Chamber at the base of the towers. The shape of the space above and between the towers suggests the letter 'T', the city's initial. The current flag received criticism when it was unveiled, particularly from those who commented that, when turned 180-degrees, the flag looks like a pair of legs with a leaf covering the crotch.^{[citation needed]}

A variation of this flag is used by Toronto Fire Services fireboat William Lyon Mackenzie. The marine Ensign consists of the main city flag in the upper canton with a life preserver on two tone blue background.

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.