Donald Michael Thomas, known as D. M. Thomas (born 27 January 1935), is a Cornish novelist, poet, playwright and translator.

Thomas was born in Redruth, Cornwall, UK. He attended Trewirgie Primary School and Redruth Grammar School before graduating with First Class Honours in English from New College, Oxford in 1959. He lived and worked in Australia and the United States before returning to his native Cornwall.

He published poetry and some prose in the British Science fiction magazine New Worlds (from 1968). The work that made him famous is his erotic and somewhat fantastical novel The White Hotel (1981), the story of a woman undergoing psychoanalysis, which has proved very popular in continental Europe and the United States. It was short-listed for the Booker Prize in 1981, coming a close second, in the view of some, to the winner, Salman Rushdie's Midnight's Children. It has also elicited considerable controversy, as some of its passages are taken from Anatoly Kuznetsov's Babi Yar, a novel about the Holocaust. In general, however, Thomas's use of such "composite material" (material taken from other sources and imitations of other writers) is seen as more postmodern than plagiarist.

In the 1950s, at height of the Cold War, Thomas studied Russian during his National Service. He retained a lifelong interest in Russian culture and literature. This culminated in a series of well-received translations of Russian poetry in the 1980s.