A referendum is the referring of a political question to an electorate for direct decision by general vote. Deriving from the Latin, ad referendum, meaning "that which must be taken back" or "that which must be submitted to an assembly," its roots lie in ancient Rome around the fourth century BC where certain laws were enacted by vote of the common people or plebians ("plebiscite"). The terms referendum and plebiscite are commonly used interchangeably but the latter term specifically denotes a vote that is advisory or consultative rather than legally binding on the government.

Referendums do not easily fit in with the traditions of British parliamentary practice and are inherently polarizing, even impassioning, processes and thus are risky undertakings for governments. However, for many observers a referendum is a useful and inherently democratic device that elicits from the electorate a precise answer to a specific question. Referendums have taken place since the 16th century in Switzerland. In France and other European countries the practice was used in the 18th century but did not spread widely until the second half of the 20th century. In Australia they are used for constitutional amendments, and some American state and local governments use them for policy and constitutional issues.

As the Canadian experience demonstrates, referendums and plebiscites may be constitutional or simply legislative, and they may be initiated either by the government or by the people. The latter take place at the local or provincial rather than national level. In Canada, the federal government has held 3 referendums (or, more strictly, plebiscites). The first was in 1898, on Prohibition, in which only 44% of the electorate voted, with 51% voting yes and 49% voting no. The second was in 1942, on Conscription, in which the Liberal government of Mackenzie King asked Canadians if they were in favour of releasing the government from its promise not to use conscripts for overseas military service. Over 60% of the voters replied yes; the others, no. In Québec, however, about 72-73% voted no.

A third referendum was held in 1992 on the Charlottetown Accord (see Constitutional History; Charlottetown Accord: Document). During the negotiations leading to the accord, several provinces had made arrangements to put any new deal to a referendum. In Québec, the government had threatened to hold a referendum on sovereignty by October if an acceptable offer was not forthcoming from the rest of Canada. Thus the referendum had become a strategic tool in the negotiations. After a new agreement was reached by the First Ministers in September, PM Brian Mulroney announced that a national referendum would be held on October 26. Seventy-five percent of eligible voters went to the polls. The accord was rejected by 6 provinces (Nova Scotia, British Columbia, Alberta, Saskatchewan, Québec and Manitoba) and one territory (Yukon). The overall vote nationally was 44.8% for and 54.2% against.

In 1948, 2 important constitutional referendums in Newfoundland were held on the issue of union with Canada. The first failed to give an absolute majority to any of the 3 options: confederation with Canada, responsible government as it existed in 1933, or Commission of Government for 5 years. But a second vote, held a month later on July 2, resulted in a slim majority (52.3%) for confederation. A Newfoundland constitutional plebiscite was held in 1996 on the question of seeking an amendment altering denominational education rights. A majority voted yes.

All the provinces, with the exception of New Brunswick, have held nonconstitutional referendums, including dealing with such matters as the prohibition of liquor and related problems; switching to daylight-saving time; votes for women; public health; ownership of electric companies; grain marketing; and in January 1988 to determine if PEI should have a fixed link to the mainland. Since Confederation there have been more than 50 provincial referendums. Four provinces - British Columbia, Alberta, Saskatchewan and Manitoba - have enacted statutes making popular initiative possible. A bill introducing popular initiative is being considered by the Ontario Legislature. Provincial referendums in Canada are traditionally consultative or advisory in nature (ie, plebiscites), although some have been treated as though they were binding by the governments that have called them.

The first Québec Referendum (1980) on the sovereignty issue was held on 20 May 1980. 60% of the voters refused to give the Parti Québécois government a mandate to negotiate Sovereignty-Association. The second Québec Referendum (1995) was held on 30 October 1995 on a question which asked voters whether they agreed "that Quebec should become sovereign after having made a formal offer to Canada for a new economic and political partnership." The result was a narrow victory for the no side, 50.6% voting no and 49.4% voting yes. Ninety-four percent of the electorate voted.