The National Capital Commission (NCC), known in French as the Commission de la capitale nationale (CCN), is a Canadian Crown corporation that administers the federally owned lands and buildings in Canada's National Capital Region, including Ottawa, Ontario and Gatineau, Quebec. The NCC was created in 1959, replacing the Federal District Commission which had been created in 1927, and had been previously called the Ottawa Improvement Commission. It reports to Parliament through the Minister of Transport, Infrastructure and Communities. The NCC is headquartered in the Chambers Building on Elgin Street, between Queen and Sparks Streets.

The role of the NCC is to champion the interests of Ottawa and surrounding region as the nation's capital, typically with regards to issues of national interest, such as the planning of monument and museum sites, events such as Canada Day, and major streetscapes such as Confederation Boulevard, a long-discussed ceremonial route linking key attractions in National Capital Region, on both sides of the Ottawa River, in Ottawa as well as Gatineau, Quebec.

This role is in contrast with those of the various municipal governments, which work for the benefit of their immediate residents on issues like road maintenance, sewer, water and public transport. The NCC also has the duty of encouraging tourism to the capital, and thus runs events such as Winterlude and Christmas Lights in the Capital. It has run the only tourist information centre in Ottawa, the Capital Infocentre, located right across from Parliament Hill, since 1996. The NCC also administers official residences such as Rideau Hall, 24 Sussex Drive and Stornoway.

The Canadian Crown is the largest employer and largest landowner in these two areas, and the NCC thus has a great deal of influence over the cities. This has sometimes been criticized as it is a non-democratic organization run by an appointed board. This was emphasized in 1998 when the NCC proposed levelling a large strip of downtown Ottawa to build a ceremonial boulevard along the city's existing Metcalfe Avenue. Over the last thirty years the activities of the NCC have been denounced or castigated by several Quebec governments. They considered municipal affairs to be a purely provincial jurisdiction, according to the constitution of Canada. Others have criticized the group for what they perceive to be poor or misguided planning decisions.

The Conservative Government of Stephen Harper, including Infrastructure Minister Lawrence Cannon, had asked for a formal review of the mandate of the NCC when taking office in 2006. In a report by a panel conducting the review, it was suggested that the Crown Corporation would require more money and become more transparent.