Niagara-on-the-Lake (2011 population 15,400) is a Canadian town located in Southern Ontario where the Niagara River meets Lake Ontario in the Niagara Region of the southern part of the province of Ontario. It is located across the Niagara River from Youngstown, New York, USA. It is the only town in Canada that has a Lord Mayor.

The town is home to the Shaw Festival, a series of theatrical productions featuring the works of George Bernard Shaw, his contemporaries, or plays about his era (1856–1950), running from April to November. The festival operates three theatres in the centre of town: the Festival, Royal George, and Court House theatres, and features one of a repertory acting company, scenic staff, and collection of resident and guest directors considered some of the best in the English-speaking world.

Along the Niagara Parkway is RiverBrink Art Museum, a popular tourist destination in Queenston. It is home to a unique collection of over 1,400 artworks and artefacts by Canadian and international artists, assembled by Samuel E. Weir. Completed in 1970, the building features Georgian-style architecture, including a mansard roof and gabled windows. It served as Weir's country residence, and was converted into an art museum following his death in 1981.

The surrounding region enjoys a comparatively mild climate thanks to the adjoining lakes, and excellent soil for fruit production, for which it has become one of Canada's centres. In particular, NOTL has grown into a major viticultural region. Visitors flock to dozens of nearby wineries, including those making the world's largest volumes of ice wine. The town is also known for its gardens, art galleries, antique shops, and golf courses. There are many hotels, inns, bed and breakfasts, vacation rentals and spas in the area.

The Town of Niagara was the site of the 8th World Scout Jamboree in 1955. Over 11,000 Scouts from 71 countries attended the Jamboree. It was the first to be held outside Europe and had the theme "Jamboree of New Horizons". Niagara-on-the-Lake was named the Prettiest Town in Canada in 1996 by Communities in Bloom, a nationwide beautification programme. The town is now a popular tourist destination, located at the northern terminus of the Niagara Parkway, a scenic drive and biking/walking path.