From 1896 known as The Clergy Endowments (Canada) Act 1791, the statute passed at Westminster in the 31st year of George III, and itemised as chapter 31 (31 Geo 3 c 31), was commonly known as the Constitutional Act 1791 (French: Acte constitutionnel de 1791). It was an Act of the Parliament of Great Britain.

The Parliament of Great Britain was formed in May 1707 following the ratification of the Acts of Union by both the Parliament of England and the Parliament of Scotland. The Acts ratified the treaty of Union which created a new unified Kingdom of Great Britain and created the parliament of Great Britain located in the former home of the English parliament in the Palace of Westminster, near the City of London. This lasted nearly a century, until the Acts of Union 1800 merged the separate British and Irish Parliaments into a single Parliament of the United Kingdom with effect from 1 January 1801.