The Lord Chancellor's Department was a United Kingdom government department. It was founded in 1885 as the Lord Chancellor's Office, to give the Lord Chancellor a staff answerable to him. It increased greatly in powers after the Courts Act 1971.

The Lord Chancellor until recently possessed the ultimate right to appoint judges to the judicial system of the United Kingdom. This is no longer the case - see the Constitutional Reform Act 2005.

In 2003 the Lord Chancellor's Department was renamed the Department for Constitutional Affairs.