Joseph Timothy Haydn (Lisbon, Portugal, 1788 - London, 17 January 1856), was a British journalist and compiler of dictionaries, well known as the author of the Dictionary of Dates, which went through many editions from 1841, and of the Book of Dignities, 1851 (3rd revised edition, 1894).

The Book of Dignities was a modernized form of Robert Beatson's Political Index, but omits the lists of holders of many important offices.

For a short time before his death, aged 69 years,[1] on 18 January 1856, Haydn had been in receipt of a small pension of £25 granted by the government.

He was buried in a common grave (no.7040) on the western side of Highgate Cemetery.

His is the first name listed on the nearby Haydn family grave where his wife Mary, sons Henry and Thomas Matthew (who purchased the grave), daughter Kate Maria and her husband Sir Frank Green, 1st Baronet are buried.