Centretown is a neighbourhood in Somerset Ward, in central Ottawa, Ontario, Canada. It is defined by the city as "the area bounded on the north by Gloucester Street and Lisgar Street, on the east by the Rideau Canal, on the south by the Queensway freeway and on the west by Bronson Avenue." Traditionally it was all of Ottawa west of the Rideau Canal, while Lower Town was everything to the east. For certain purposes, such as the census and real estate listings, the Golden Triangle and/or Downtown Ottawa is included in Centretown and it is considered part of Centretown by the Centretown Citizens Community Association as well as being used in this way in casual conversation.

Ottawa is the capital city of Canada. It is located in the southern portion of the province of Ontario, at the confluence of the Ottawa River and the Rideau River. Ottawa borders Gatineau, Quebec, and forms the core of the Ottawa–Gatineau census metropolitan area (CMA) and the National Capital Region (NCR). As of 2021, Ottawa had a city population of 1,017,449 and a metropolitan population of 1,488,307, making it the fourth-largest city and fourth-largest metropolitan area in Canada.