Events that occurred on 13 August
 On Earth
- 1867 - Professor William Craigie is born.
- 1917 – J.R.R. Tolkien is admitted to Brooklands Officers' Hospital in Hull for the first time.
- 1976 - Mythcon 7 in Sacramento, California.
- 1978 - Mythcon 9 in West Sacramento, California.
- 1982 - Mythcon 13 at Chapman College in Orange, California.
- 1983 - Mythcon 14 at Scripps College in Claremont, California.
- 1984 - Mythcon 15 at Mills College in Oakland, California.
- 2002 - The Battlelore album ...Where the Shadows Lie is released.
- 2005 - The Tolkien Society's Tolkien 2005 conference in Birmingham, England.
- 2010 - "Edge of the Wild", Tolkien art exhibition in Moreton-in-Marsh, England.
- 2010 - Fantasy, Myth and the Measure of Truth is released in paperback.
- 2011 - Omentielva Cantea - 4th International Conference on Tolkien's Invented Languages in Valencia, Spain.
- 2017 - Omentielva Otsea - the Seventh International Conference on Tolkien's Invented Languages at California State University, East Bay.