This coat of arms was granted after confederation in 1868, with supporters and crest added in 1909. The gold maple leaves represent Ontario (in distinction from green leaves (Quebec) or red leaves (Canada)), as maples are common in this province. The cross of St. George, in the chief, represents the English heritage of many of the people in Ontario (although this is no longer as true as it was when the arms were first granted, of course), as well as being a reference to King George III, under whose rule the colony of Upper Canada was established.

The supporters, a moose and a deer, are two of the original inhabitants of the area, as is the black bear (in the crest). The motto reads UT INCEPIT FIDELIS SIC PERMANET, which is normally translated as "Loyal she began, loyal she remains", a reference to the founding of the province by the United Empire Loyalists, who fled from the United States when the yanks decided to stop being British.

The other emblems of Ontario can be found here and here.