John Bordley Rawls (February 21, 1921 – November 24, 2002) was an American philosopher and a leading figure in moral and political philosophy. He held the James Bryant Conant University Professorship at Harvard. His magnum opus, A Theory of Justice (1971), is now regarded as "one of the primary texts in political philosophy." His work in political philosophy, dubbed Rawlsianism, takes as its starting point the argument that "most reasonable principles of justice are those everyone would accept and agree to from a fair position." Rawls employs a number of thought experiments—including the famous veil of ignorance—to determine what constitutes a fair agreement in which "everyone is impartially situated as equals," in order to determine principles of social justice. He is one of the major thinkers in the tradition of liberal political philosophy.

Rawls received both the Schock Prize for Logic and Philosophy and the National Humanities Medal in 1999, the latter presented by President Bill Clinton, in recognition of how Rawls' work "helped a whole generation of learned Americans revive their faith in democracy itself."

John Rawls was born in Baltimore, Maryland. He was the second of five sons to William Lee Rawls and Anna Abell Stump. Rawls attended school in Baltimore for a short time before transferring to Kent School, an Episcopalian preparatory school in Connecticut. Upon graduation in 1939, Rawls attended Princeton University, and was accepted into the The Ivy Club. During his last two years at Princeton he “became deeply concerned with theology and its doctrines”. He considered attending a seminary to study for the Episcopal priesthood. In 1943, he completed his Bachelor of Arts degree and joined the Army. During World War II, Rawls served as an infantryman in the Pacific, where he toured New Guinea, the Philippines, and Japan; There, he witnessed the aftermath of the bombing of Hiroshima. After this experience, Rawls turned down an offer to become an officer and left the army as a private in 1946. Shortly thereafter, he returned to Princeton to pursue a doctorate in moral philosophy.

Rawls married Margaret Fox, a Brown University graduate, in 1949.

After earning his Ph.D. from Princeton in 1950, Rawls taught there until 1952, when he received a Fulbright Fellowship to Oxford University (Christ Church), where he was influenced by the liberal political theorist and historian Isaiah Berlin and the legal theorist H.L.A. Hart. After returning to the United States, he served first as an assistant and then associate professor at Cornell University. In 1962, he became a full professor of philosophy at Cornell, and soon achieved a tenured position at MIT. That same year, he moved to Harvard University, where he taught for almost forty years, and where he trained some of the contemporary figures in moral and political philosophy, including Martha Nussbaum, Thomas Nagel, Onora O'Neill, Christine Korsgaard, Susan Neiman and Thomas Pogge.

Rawls seldom gave interviews and had a "bat-like horror of the limelight," so despite his celebrity, he did not become a public intellectual and remained committed mainly to his academic and family life. He suffered the first of several strokes in 1995, which severely impeded his ability to continue working. Nevertheless, he was still able to complete a work entitled The Law of Peoples, which contains the most complete statement of his views on international justice. Shortly before his death in November 2002, he published Justice As Fairness: A Restatement, in which he responds to criticisms of A Theory of Justice and revises his ideas. This last work indicates a "leftward shift" in his thought.

Rawls is noted for his contributions to liberal political philosophy. Among the ideas from Rawls' work that have received wide attention are:

There is general agreement in academia that the publication of A Theory of Justice in 1971 was important to a revival, during the 1960s and 1970s, in the academic study of political philosophy. His work has crossed disciplinary lines, receiving serious attention from economists, legal scholars, political scientists, sociologists, healthcare resource allocators, and theologians. Rawls has the unique distinction among contemporary political philosophers of being frequently cited by the courts of law in the United States and referred to by practicing politicians in the United States and United Kingdom.

In A Theory of Justice, Rawls attempts to reconcile freedom and equality in a principled way, offering an account of "justice as fairness." Central to this effort is his famous approach to the seemingly intractable problem of distributive justice.