The Manitoba Act was given Royal Assent in the 33rd year of Queen Victoria's reign, May 12, 1870. Taking effect on July 15, 1870, the Manitoba Act created the Province of Manitoba. The Manitoba Act is a Canadian Statute, and is still part of the Constitution of Canada.

It was adopted by Parliament in response to the Metis concerns of the provisional government led by Louis Riel. Riel was a major influence on the Manitoba Act since it was based on his list of rights. The Red River colony and its surroundings would become the province of Manitoba, which was a tiny area around the Red River Colony. Unlike other provinces, however, Manitoba would have its land and other resources initially controlled by Ottawa. The victory for the Métis was the guarantee that they would receive title for the lands they already farmed and of farmland for the use of their children. As a result of the settlement, however, Macdonald convinced the British to send a military expedition to Manitoba, led by Colonel Wolseley. White settlers poured into the province, and the Métis were kept waiting for their land grants. Many Métis fled to Saskatchewan and Louis Riel fled to the United States.

The Manitoba Act contained religious and language rights, namely rights to denominational schools and rights to laws in both French and English. This has led to political controversies, however, including the Manitoba Schools Question in the nineteenth century, as denominational school rights were curtailed. The legislature also enacted English-only laws later found unconstitutional by the Supreme Court of Canada in the case Reference re Manitoba Language Rights (1985).

de:Manitoba Act fr:Loi sur le Manitoba pl:Ustawa o Manitobie