The Lord Chancellor, formally the Lord High Chancellor of Great Britain, is the highest-ranking traditional minister among the Great Officers of State in Scotland and England in the United Kingdom, nominally outranking the prime minister. The lord chancellor is appointed by the sovereign on the advice of the prime minister. Prior to their Union into the Kingdom of Great Britain, there were separate lord chancellors for the Kingdom of England (including Wales) and the Kingdom of Scotland; there were lord chancellors of Ireland until 1922.

The lord chancellor is a member of the Cabinet and is, by law, responsible for the efficient functioning and independence of the courts. In 2005, there were a number of changes to the legal system and to the office of the lord chancellor. Formerly, the lord chancellor was also the presiding officer of the House of Lords, the head of the judiciary of England and Wales and the presiding judge of the Chancery Division of the High Court of Justice. The Constitutional Reform Act 2005 transferred these roles to the Lord Speaker, the Lord Chief Justice and the Chancellor of the High Court respectively. The current lord chancellor is Dominic Raab, who is also the Secretary of State for Justice.

One of the lord chancellor's responsibilities is to act as the custodian of the Great Seal of the Realm, kept historically in the Lord Chancellor's Purse. A lord keeper of the Great Seal may be appointed instead of a lord chancellor. The two offices entail exactly the same duties; the only distinction is in the mode of appointment. Furthermore, the office of lord chancellor may be exercised by a committee of individuals known as Lords Commissioners of the Great Seal, usually when there is a delay between an outgoing chancellor and their replacement. The office is then said to be in commission. Since the 19th century, however, only lord chancellors have been appointed, the other offices having fallen into disuse.