Mark D. Sacks (29 December 1953 – 17 June 2008) was a British philosopher best known for his work on Kant, Post-Kantian idealism, and the epistemological tradition in European Philosophy.
He was a professor of philosophy at the University of Essex until his death.
His first degree was in philosophy, at Hebrew University of Jerusalem.
He obtained a doctorate in philosophy from King's College, Cambridge, under the supervision of Bernard Williams.
He died from prostate cancer at the age of 54.