Section 91 of the Constitution Act, 1867

Section 91 of the Constitution Act, 1867 (French: article 91 de la Loi constitutionnelle de 1867) is a provision in the Constitution of Canada that sets out the legislative powers of the federal Parliament. The federal powers in section 91 are balanced by the list of provincial legislative powers set out in section 92 of the Constitution Act, 1867. The dynamic tension between these two sets of legislative authority is generally known as the "division of powers". The interplay between the two lists of powers have been the source of much constitutional litigation since the Confederation of Canada in 1867.

The Constitution Act, 1867 is the constitutional statute which established Canada. Originally named the British North America Act, 1867, the Act continues to be the foundational statute for the Constitution of Canada, although it has been amended many times since 1867. It is now recognised as part of the supreme law of Canada.