Events that occurred on 17 December.
 On Earth
- 1910 – J.R.R. Tolkien is awarded an Open Classical Exhibition for classical languages to Exeter College.
- 1936 – Actress Marian Diamond is born.
- 1937 - Charles Furth writes a letter to J.R.R. Tolkien.
- 1944 - Actor Bernard Hill is born.
- 1947 - J.R.R. Tolkien writes a letter to Malcolm Knox.
- 1967 - J.R.R. Tolkien and his wife went to see The Hobbit musical performance.
- 1972 - J.R.R. Tolkien writes Letter 347.
- 2003 – The Lord of the Rings: The Return of the King is released in cinemas.
- 2003 - Actor Alan Tilvern dies.
- 2014 - The Hobbit: The Battle of the Five Armies is released in the United States.
- 2017 - "There Would Always Be a Fairy-Tale": Essays on Tolkien's Middle-earth is published.