The House of Lords Act 1999 was an Act of the Parliament of the United Kingdom that was given Royal Assent on 11 November 1999. The Act reformed the House of Lords, one of the chambers of Parliament. For centuries, the House of Lords had included several hundred members who inherited their seats; the Act removed such a right. However, as part of a compromise, the Act did permit ninety-two hereditary peers to remain in the House on an interim basis. Another ten were created life peers to enable them to remain in the House.
The Act decreased the membership of the House from 1,330 in October 1999 to 669 in March 2000.