Events that occurred on 17 August
 On Earth
- 1953 – J.R.R. Tolkien agrees with Rayner Unwin on the book titles for his sequel to The Hobbit: they will be The Fellowship of the Ring, The Two Towers and The Return of the King.
- 1971 - Linguist Helge Fauskanger is born.
- 1973 - Mythcon IV in Santa Barbara, California.
- 1975 - Mythcon VI at Scripps College in Claremont, California.
- 1992 - Tolkien Centenary Conference, a combination of Oxonmoot 1992 and Mythcon XXIII, at Keble College, Oxford.
- 2008 - Mythcon XXXIX at Central Connecticut State University in New Britain, Connecticut.
- 2012 - The Return of the Ring, Tolkien Society conference at Loughborough University, England.