University of Paris-Sud (University of Paris XI) is a French university distributed among several campuses in the southern suburb of Paris (including Orsay, Cachan, Châtenay-Malabry, Sceaux and Kremlin-Bicêtre campuses). The main campus is located in Orsay (48.699890°N 2.173309°E). This university is a member of the UniverSud Paris and a constituent university of the federal University of Paris-Saclay.

Paris-Sud is one of the largest and most renowned French universities, particularly in science and mathematics. Paris-Sud is ranked 2nd in France, 7th in Europe and 39th worldwide by the 2013 Academic Ranking of World Universities (ARWU). Furthermore, in this latest edition of ARWU ranking, the university is ranked 15th globally in the field of Natural Sciences and Mathematics; in the five general subject rankings, the university is ranked 7th in mathematics and 19th in physics.