The Regional Municipality of Niagara (2006 population: 427,421), also known as the Niagara Region, or, colloquially, "Regional Niagara", is a regional municipality comprising twelve municipalities of southern Ontario, Canada. Niagara Falls, Port Colborne, St. Catharines, Thorold, Welland, Fort Erie, Grimsby, Lincoln, Niagara-on-the-Lake, Pelham, Wainfleet and West Lincoln.

The region occupies most of the Niagara Peninsula. Its eastern boundary is the Niagara River, which is also the border with the United States. It is bounded on the north by Lake Ontario and on the south by Lake Erie.

The Niagara Region is an important centre for agriculture and tourism in Canada. The most important agricultural enterprise in Niagara is viticulture, or winemaking. The Niagara Wine Route, which connects visitors to dozens of wineries, is a growing tourism draw. The Niagara Grape & Wine Festival is a non-profit organization that presents three popular wine festivals in St. Catharines and Niagara during the year. While the internationally-renowned Niagara Falls is one of Canada's major tourist attractions. Along with Shaw Festival, held annually in Niagara-on-the-Lake, and the Welland Canal, the Regional Municipality of Niagara receives up to 12 million visitors each year.