Events that occurred on 28 May.
- 1937 - J.R.R. Tolkien writes Letter 14.
- 1938 - J.R.R. Tolkien writes a letter to Kenneth Sisam.
- 1964 - Tree and Leaf is first published in the UK.
- 1965 - J.R.R. Tolkien writes to an unknown reader.
- 1969 - J.R.R. Tolkien writes a letter to Anthony D. Howlett.
- 1980 - Second edition of The Languages of Tolkien's Middle-earth is published.
- There are no known events on this day.