Henry Arundell, 3rd Baron Arundell of Wardour, PC was a Peer of England during the 17th century, and the most famous of the Lords Arundell of Wardour. He served as Lord Privy Seal and Lord High Steward, and was appointed to the Privy Council. During the Popish Plot he suffered a long period of imprisonment, although he was never brought to trial.

The Lord Privy Seal is the fifth of the Great Officers of State in the United Kingdom, ranking beneath the Lord President of the Council and above the Lord Great Chamberlain. Originally, its holder was responsible for the monarch's personal (privy) seal until the use of such a seal became obsolete. Though one of the oldest offices in European governments, it has no particular function today because the use of a privy seal has been obsolete for centuries; it may be regarded as a traditional sinecure, but today, the holder of the office is invariably given a seat in the Cabinet of the United Kingdom, and is sometimes referred to as a minister without portfolio.