The Canadian province of Newfoundland and Labrador has a unicameral legislature, the General Assembly composed of the Lieutenant Governor and the House of Assembly, which operates on the Westminster system of government. The executive function of government is formed by the Lieutenant Governor, the premier (head of government, and normally the leader of the largest party in the legislature) and his or her cabinet.

Newfoundland was first inhabited by the Beothuk and the Maritime Archaic, while Labrador was first inhabited by the Dorset, Thule, and later Inuit and Innu. It has the first known European settlement in the Americas at L'Anse aux Meadows, built by the Vikings circa 1020 A.D. The island of Newfoundland and the coast of Labrador has been colonized or settled by a number of European nations including England and France.

The emergence of a common law system and political institutions was slow. Law and order was initially the responsibility of fishing captains and admirals and military governors in the 17th and 18th centuries. With permanent settlement however, this system was eventually replaced by civil officials and in 1832 representative government. This meant that a colonial assembly would share power with an appointed Legislative Council. In 1854, Newfoundland was granted responsible government, and it attained Dominion status in 1907.

The Dominion of Newfoundland was a highly polarized society, marked by distinct cleavages between Roman Catholics and Protestants, Liberals and Conservatives, descendants of Irish and West Country English, rich merchants and poor fishermen and tradesmen, and rural Newfoundland versus St. John's (or alternatively the Avalon Peninsula against the rest of the Dominion's districts). This often manifested itself in hotly contested and even violent elections. Various reforms in the 1860s and 1870s (during which Newfoundland rejected confederation with Canada) quelled the often hostile nature of this polarization.

With exceptions throughout its Dominion history, class, religion and political parties tended to align such that Irish Catholics tended to support the Liberal Party and English Protestants tended to support the Conservative Party.

Newfoundland and Labrador's present-day boundaries were finalized as a result of the British Privy Council's decision in the Labrador Boundary Dispute of 1927, to cede much of inland Labrador to the Dominion of Newfoundland rather than to the Canadian province of Quebec.

As a result of the Great Depression, Newfoundland's economy deteriorated. This resulted in a famous episode in 1932 when a large riot erupted at the Colonial Building and then Prime Minister Richard Squires narrowly escaped. The Dominion assembly approved the recommendations of the Amulree Commission the following year and voted itself out of existence in order to be replaced by an appointed Commission of Government. This commission was effectively an appointed council with a British Governor and six commissioners from both Britain and Newfoundland. The Commission oversaw slow growth during the beginning of its reign, but Newfoundland began to thrive during World War II.

It was shortly after the Second World War that a Newfoundland National Convention was created in order to deliberate the constitutional future of Newfoundland. Two referendums were initiated in the year 1948. In the first, Newfoundlanders were asked to vote on whether to join Canada as a province, return to an independent dominion with responsible government, or continue with an appointed Commission. In the second referendum, Newfoundlanders were asked to choose between responsible government and confederation with Canada. The movement for responsible government tended to be weaker, less organized in rural areas, and had some divisions stemming from many of its members supporting a special economic union with the United States. Newfoundland's voters narrowly voted in favour of confederation and in 1949 Newfoundland joined Canada as its tenth province.