Byward Market (named for John By and sometimes called By Ward Market, ByWard Market or simply The Market) is a neighbourhood in Ottawa, Ontario located just east and north of downtown. It is bordered on the west by the Rideau Canal and on the east by the Rideau River. To the north it stretches to the Ottawa River area while to the south it is bordered by Rideau Street. The area is named for the small open air market located near its south west corner.

During the growth of Bytown (the former name for Ottawa) in the 19th century the Byward Market area was called Lowertown and most residents were Irish or French. The battles between these communities became the stuff of legend, although, as Catholics, both united in common cause against the wealthier Protestants. The large Catholic community attracted Notre Dame Cathedral, one of the biggest and oldest Roman Catholic churches in Ottawa. The shape of the cathedral was taken into account when the National Gallery of Canada was designed and built across Sussex Drive.

A multitude of restaurants and specialty food stores have sprouted around the market area, making this neighborhood one of the liveliest in Ottawa after normal business hours. A four block area around the market provides the densest concentration of eating places in the National Capital Region, but the areas beyond this zone also offer boutiques and restaurants in abundance.

Over the years the city has developed a series of five small, human-scale, open air courtyards, immediately east of Sussex Drive, stretching from Saint Patrick Street to George Street. These cobblestone courtyards are filled with flowers, park benches, fountains and sculptures. Several of the houses surrounding them are historic buildings.

The neighbourhood is today a very mixed one with yuppie couples, many families and some homeless people. At one time, the area had a serious prostitution problem, which was remedied with a controversial rerouting of streets through much of the residential area. Crime remains an issue, however. The area is mainly English-speaking but there is a large francophone population as well. The Market is close to downtown, to the Rideau Centre shopping mall, to Parliament Hill and to a number of foreign embassies.

See also: List of Ottawa neighbourhoods