The Parliament Acts 1911 and 1949 are two Acts of the Parliament of the United Kingdom, which form part of the constitution of the United Kingdom. Section 2(2) of the Parliament Act 1949 provides that the two Acts are to be construed as one.

The Parliament of the United Kingdom of Great Britain and Northern Ireland is the supreme legislative body of the United Kingdom, and may also legislate for the Crown Dependencies and the British Overseas Territories. It meets at the Palace of Westminster in London. Parliament possesses legislative supremacy and thereby holds ultimate power over all other political bodies in the United Kingdom and the Overseas Territories. While Parliament is bicameral, it has three parts: the sovereign, the House of Lords, and the House of Commons. The three parts acting together to legislate may be described as the King-in-Parliament. The Crown normally acts on the advice of the prime minister, and the powers of the House of Lords are limited to only delaying legislation; thus power is de facto vested in the House of Commons.