Ottawa—Vanier (formerly known as Ottawa East) is a federal electoral district in Ontario, Canada, that has been represented in the House of Commons of Canada since 1935. Previous to that date, it was part of the Ottawa electoral district that returned two members.

The riding generally corresponds to the wards of Beacon Hill-Cyrville, Rideau-Rockcliffe and Rideau-Vanier.

The riding became vacant because of the death of incumbent MP Mauril Bélanger on August 16, 2016. Mona Fortier was elected in the byelection to fill the seat on April 3, 2017.

The riding, with a large Franco-Ontarian population in Vanier, is one of the most solidly Liberal in the country, having elected Liberals both federally and provincially in every election since its creation. In fact, the previous electoral district which comprises most of the constituency, Russell, had been solidly Liberal since 1887. The riding is home to many civil servants.

About 15% of the riding is in the former city of Vanier, which was amalgamated into Ottawa in 2001. Vanier has long been home to much of Ottawa's francophone population, a group that has traditionally been solidly Liberal. The riding also contains the wealthiest part of Ottawa, the former village Rockcliffe Park, which has supported both the Conservatives, and the Liberals in recent elections. The anglophone middle class neighbourhoods of Sandy Hill, containing the University of Ottawa, and New Edinburgh also tend to vote Liberal, but with significant support for the New Democratic Party. In 2011, the NDP won Sandy Hill, Lower Town, Vanier and in Overbrook. The Conservatives won in the more suburban parts of the riding like in Beacon Hill and Pineview.

In 2003, it was redefined as the part of the City of Ottawa east and north of a line running south along the Rideau Canal from the interprovincial boundary to Mann Avenue, northeast to Nicholas Street, southeast to Highway 417, and east to the abandoned Canadian Pacific Railway to the hydroelectric transmission line, north to Innes Road, northeast to Blair Road, northwest to Montreal Road, east and northeast to Regional Road 174, northeast to Green's Creek, north to the Ottawa River.

According to the 2021 Canadian census

Ethnic groups: 60.2% White, 14.5% Black, 5.5% Indigenous, 5.2% Arab, 3.6% South Asian, 2.8% Chinese, 1.9% Latin American, 1.6% Filipino, 1.5% West Asian

Languages: 47.1% English, 23.5% French, 4.2% Arabic, 1.9% Spanish, 1.3% Mandarin

Religions: 53.8% Christian (33.5% Catholic, 3.1% Anglican, 2.0% United Church, 1.8% Christian Orthodox, 1.1% Pentecostal, 12.3% Other), 9.5% Muslim, 32.8% None

Median income: $42,400 (2020)

Average income: $57,600 (2020)

The federal riding was created as "Ottawa East" in 1933 from parts of Ottawa and Russell ridings.

It initially consisted of, in the city of Ottawa, Rideau, Ottawa, By, St. Georges wards and the northeast part of Riverdale Ward, the town of Eastview, and the village of Rockcliffe Park.

In 1947, it was redefined to exclude the town of Eastview. In 1952, it was redefined to consist of the village of Rockcliffe Park, and the eastern parts of the city of Ottawa. In 1966, it was redefined to include the City of Eastview and exclude the village of Rockcliffe Park.

The name of the electoral district was changed in 1973 to "Ottawa—Vanier".

In 1976, it was redefined to consist of the City of Vanier, and the eastern parts of the city of Ottawa. In 1987, it was redefined to consist of the City of Vanier, the eastern part of the city of Ottawa, part of the city of Gloucester and the Village of Rockcliffe Park. In 1996, the Ottawa and Gloucester parts of the riding were redefined.

In 2003, it was given its current boundaries that are described above.

Following the Canadian federal electoral redistribution, 2012, the riding gained the neighbourhood of Beacon Hill South from Ottawa—Orléans.

Following the 2022 Canadian federal electoral redistribution, this riding will be renamed Ottawa—Vanier—Gloucester at the first election held after approximately April 2024. It will gain Blackburn Hamlet from Orléans and will lose a small territory south of Innes Road to Prescott—Russell—Cumberland.

This riding has elected the following members of Parliament:

Parliament	Years	Member		Party
Ottawa East Riding created from Ottawa and Russell
18th	1935–1936		Edgar-Rodolphe-Eugène Chevrier	Liberal
	1936–1940		Joseph-Albert Pinard
19th	1940–1945
20th	1945–1949		Jean-Thomas Richard
21st	1949–1953
22nd	1953–1957
23rd	1957–1958
24th	1958–1962
25th	1962–1963
26th	1963–1965
27th	1965–1968
28th	1968–1972
29th	1972–1974		Jean-Robert Gauthier
Ottawa—Vanier
30th	1974–1979		Jean-Robert Gauthier	Liberal
31st	1979–1980
32nd	1980–1984
33rd	1984–1988
34th	1988–1993
35th	1993–1994
	1995–1997		Mauril Bélanger
36th	1997–2000
37th	2000–2004
38th	2004–2006
39th	2006–2008
40th	2008–2011
41st	2011–2015
42nd	2015–2016
	2017–2019		Mona Fortier
43rd	2019–2021
44th	2021–present