René Frédéric Thom (French: [ʁəne tɔm]; 2 September 1923 – 25 October 2002) was a French mathematician, who received the Fields Medal in 1958.

He made his reputation as a topologist, moving on to aspects of what would be called singularity theory; he became world-famous among the wider academic community and the educated general public for one aspect of this latter interest, his work as founder of catastrophe theory (later developed by Christopher Zeeman).^{[1][2][3][4][5]}