The University of Rennes (French: Université de Rennes) is a public research university located in Rennes, Upper Brittany, France. Originally founded in 1460, the university was split into two universities in 1970: Rennes 1 University and Rennes 2 University. On 1 January 2023, the Rennes 1 University merged with five grandes écoles—EHESP, École nationale supérieure de chimie de Rennes, ENS Rennes, INSA Rennes and Sciences-Po Rennes—to create the new University of Rennes.

The University of Rennes 2 with other research institutes (CNRS, INRAE, Inria, Inserm and CHU de Rennes) are associated with the 'UNIR' project. The six establishments will be grouped together in an 'Experimental Public Establishment' (EPE), weighing nearly 7,000 staff and teachers, including a thousand researchers, 156 research laboratories and 60,000 of the 68,000 students in the Breton capital, including 7,000 international students.