Niagara-on-the-Lake (2001 population 13,839) is a town where the Niagara River meets Lake Ontario in Ontario, Canada. It is located across from Youngstown, New York.

First known as Butlersburg, Niagara-on-the-Lake was incorporated in 1781 as the Town of Newark when Loyalists fled the United States during the American Revolution.

In 1792 the newly renamed Niagara was named the capital of Upper Canada, but lost that distinction to Toronto as Niagara-on-the-Lake's proximity to the United States presented a danger. During war of 1812 - 1814, American forces captured and later destroyed the town before they withdrew. The British rebuilt, however, and today it has retained much of its historical charm. The present name was adopted around 1880 to distinguish the town from Niagara Falls.

Niagara-on-the-Lake, said to be the prettiest town in Canada, is now a tourist magnet. Most of the former military sites have been restored, and there are also many wineries, inns and spas in the area. It is the home of the Shaw Festival.