Arthur Norman Prior (1914 Masterton, New Zealand – 1969 Trondheim, Norway) was one of the foremost logicians of the twentieth century. Prior (1957) founded tense logic, now also known as temporal logic, and made important contributions to intensional logic, particularly in Prior (1971).

Prior was entirely educated in New Zealand, where he was fortunate to have come under the influence of John Findlay. Despite knowing only modest mathematics, he began teaching philosophy and logic at Canterbury University College in 1946, filling the vacancy created by Karl Popper's resignation. He became Professor in 1953. Thanks to the good offices of Gilbert Ryle, who had met Prior in New Zealand in 1954, Prior spent the year 1956 on leave at the University of Oxford, where he gave the John Locke lectures in philosophy. During his time at Oxford, he met Peter Geach and William Kneale, influenced John Lemmon, and corresponded with the adolescent Saul Kripke. Logic in the United Kingdom was then in a rather low state, and Prior's enthusiasm is believed to have contributed materially to its revival. From 1959 to 1966, he was Professor of Philosophy at the University of Manchester. From 1966 until his death he was Fellow and Tutor in philosophy at Balliol College, Oxford. His students include Max Cresswell, Kit Fine, and Robert Bull.

Almost entirely self-taught in modern formal logic, Prior published his first paper on logic in 1952, when he was already 38 years of age, shortly after discovering the work of Józef Maria Bocheński and Jan Łukasiewicz, very little of whose work was then translated into English. He went on to employ Polish notation throughout his career. Prior (1955) distills much of his early teaching of logic in New Zealand.