Events that occurred on 18 August
 On Earth
- 1945 - Eric Rücker Eddison dies.
- 1973 - Mythcon 4 in Santa Barbara, California.
- 1975 - Mythcon 6 at Scripps College in Claremont, California.
- 1992 - Tolkien Centenary Conference, a combination of Oxonmoot 1992 and Mythcon 23, at Keble College, Oxford.
- 1997 - The audiobook Pearl and Sir Orfeo by J.R.R. Tolkien, read by Terry Jones, is published.
- 2000 - Mythcon 31 in Hawaii.
- 2008 - Mythcon 39 at Central Connecticut State University in New Britain, Connecticut.
- 2012 - The Return of the Ring, Tolkien Society conference at Loughborough University, England.
 In Arda
- T.A. 3018:
- T.A. 3019: