The Official Opposition Shadow Cabinet, or His Majesty’s Most Loyal Opposition Shadow Cabinet, but usually simply the Shadow Cabinet, is the committee of senior members of the Official Opposition who scrutinise the work of the Cabinet of the United Kingdom. Each Shadow Cabinet member is typically given a position which corresponds to that of a government minister in Cabinet. Shadow Cabinet members, known as Shadow Ministers, are usually appointed by the Leader of the Opposition (currently Sir Keir Starmer). The role of a Shadow Minister is to develop alternative policies, hold the government to account for its actions and responses, and act as spokespeople for the opposition party in their own specific policy areas.^[1] By convention, Shadow Ministers are either serving members of the House of Commons or the House of Lords, with most chosen from the former. Since May 2010, Labour has been the Official Opposition, and its leadership therefore forms the current Shadow Cabinet.

Not all opposition frontbenchers are members of the Shadow Cabinet, which is composed of the most senior opposition members (usually around twenty).

The Leader of the Opposition, the Opposition Chief Whip and Opposition Deputy Chief Whip are the only members of the Official Opposition in the House of Commons to be paid for their opposition roles in addition to their salaries as Members of Parliament. The Leader of the Opposition and the Opposition Chief Whip in the House of Lords also receive a salary.