Section 125 of the Constitution Act, 1867 is a provision of the Constitution of Canada relating to taxation immunities of the federal and provincial governments. The section provides that the property of the provincial and federal governments are not subject to taxation.

The Constitution Act, 1867, originally enacted as the British North America Act, 1867, is a major part of the Constitution of Canada. The act created a federal dominion and defines much of the operation of the Government of Canada, including its federal structure, the House of Commons, the Senate, the justice system, and the taxation system. In 1982, with the patriation of the Constitution, the British North America Acts which were originally enacted by the British Parliament, including this Act, were renamed. However, the acts are still known by their original names in records of the United Kingdom. Amendments were also made at this time: section 92A was added, giving provinces greater control over non-renewable natural resources.