Events that occurred on 20 October.
 On Earth
- 1911 - J.R.R. Tolkien signs a Oxford University visitor's page.
- 1949 - Farmer Giles of Ham is published.
- 1955 - The Return of the King is published.
- 1958 - Actor Viggo Mortensen is born.
- 1965 - J.R.R. Tolkien writes Letter 278.
- 1965 - J.R.R. Tolkien writes a letter to Timothy J. Wheeler.
- 1968 - Strange Lodgings, the fourth episode of the 1968 radio series of The Hobbit, is aired on BBC Radio.
- 1994 - The War of the Jewels is published in the UK.
- 2005 - George Sayer, friend of J.R.R. Tolkien, dies.