Sir Thomas Malcolm Knox FRSE (28 November 1900 – 6 April 1980) was a British philosopher who served as Principal of St Andrews University from 1953 to 1966 and vice-president of the Royal Society of Edinburgh from 1975 to 1978.
He was educated at Bury Grammar School and the Liverpool Institute, and then at Pembroke College, Oxford where he obtained a first-class degree in Literae Humaniores in 1923.
His first wife died in 1930 and in the following year he became Bursar-Fellow and lecturer in philosophy at Jesus College, Oxford, later becoming a Fellow and Tutor.
His interests did not fit in with those then prevailing at Oxford and so he moved to St Andrews University as Professor of Moral Philosophy in 1936, serving also as deputy principal and head of department.
However, he later concluded that separation of the two could not be avoided and then decided that it would not be proper to continue in his position as his stated policy had changed.