The leader of the House of Lords is a member of the Cabinet of the United Kingdom who is responsible for arranging government business in the House of Lords. The post is also the leader of the governing party in the House of Lords who acts as the government party chairperson in the house. The role is always held in combination with a formal Cabinet position, usually one of the sinecure offices of Lord President of the Council, Lord Keeper of the Privy Seal or Chancellor of the Duchy of Lancaster. Unless the Leader is also a departmental minister, being Leader constitutes the bulk of their government responsibilities, but it has never been an independent salaried office. The Office of the Leader of the House of Lords is a ministerial department.

The Cabinet of the United Kingdom is the senior decision-making body of His Majesty's Government. A committee of the Privy Council, it is chaired by the Prime Minister and its members include Secretaries of State and other senior ministers. Members of the Cabinet are appointed by the Prime Minister and are by convention chosen from members of the two houses of the Parliament of the United Kingdom, the House of Commons and the House of Lords.