Events that occurred on 25 August
 On Earth
- 1900 - Author and philosopher Friedrich Nietzche dies.
- 1930 - Actor Bruce Allpress is born.
- 1947 - Artist Michael Kaluta is born.
- 1957 - Author Ian Brodie is born.
- 1963 - Actress Brianne Siddall is born.
- 1971 - J.R.R. Tolkien writes Letter 327.
- 1973 - J.R.R. Tolkien writes a letter to Glyn Daniel
- 1974 - Mythcon 5 at Scripps College in Claremont, California.
- 1988 - The Return of the Shadow is published in the UK.
- 2003 - Starter decks of "The Countdown Collection", a special set of The Lord of the Rings Trading Card Game, are released.
- 2006 - The Oxford Tolkien Conference at Exeter College, Oxford.
- 2007 - The Tolkien Society's Australian Seminar 2007 in Sydney, Australia.
- 2010 - A middle English vocabulary is published.