For the electoral district, see Kitchener—Waterloo (electoral district).

The Regional Municipality of Waterloo is a regional municipality located in Southern Ontario, Canada. It consists of the cities of Kitchener, Cambridge, and Waterloo (collectively called the Tri-Cities), and the townships of Wellesley, Woolwich, Wilmot, and North Dumfries. It is often referred to as the Region of Waterloo or just Waterloo Region. The Region is 1369 square kilometres in size and its regional seat of government is in Kitchener. The Region's population was 507,096 at the 2011 census.