Alan Gradon Thomas (19 October 1911, Hampstead, London – 3 August 1992), was an English bibliophile.
After Durrell's death, Thomas donated a significant collection of books, journals and other materials of or pertaining to Durrell to the British Library.
He became 'a kind of extra brother to the boys and a lifelong friend'.
In 1937 he visited the author on Corfu, recording his impressions of the trip in a private diary.
Thomas wrote several other books on different topics, including Lawrence Durrell's life and works, and antiquarian book collecting, including: A collection of Thomas's letters to James A. Brigham is held at the University of Victoria.