public, coeducational institution of higher education in Carbondale and Edwardsville, Illinois, U.S. It was chartered in 1869 as Southern Illinois Normal University and opened that same year. It grew to become one of the largest teachers colleges in the state. In 1943 the university began offering graduate-level course work, and in 1947 it was renamed Southern Illinois University. The first doctorate was awarded in 1959. In 1957 the university founded two academic centres, in Alton and East St. Louis (East Saint Louis). The success of these centres spurred the creation of the Edwardsville campus, located on bluffs along the Mississippi River, which opened in 1965. Total enrollment on the two campuses is about 35,000.

The Carbondale and Edwardsville campuses offer a wide range of bachelor's, master's, doctoral, and professional degree programs. The main institution at Carbondale comprises eight colleges and three schools, including a law school. It also operates a medical school in Springfield and a campus in Niigata, Japan. The Edwardsville branch is made up of one college and six schools, including the School of Dental Medicine in Alton. Research facilities at Carbondale include the Center for Archaeological Investigations, the Fisheries and Illinois Aquaculture Center, the Coal Research Center, the Paul Simon Public Policy Institute, and the Materials Technology Center. The Morris Library contains more than 2.5 million volumes, including a notable collection on philosopher John Dewey (Dewey, John). The Environmental Resources Training Center was founded at Edwardsville in 1977. Among noteworthy faculty members at Southern Illinois University were architect R. Buckminster Fuller (Fuller, R Buckminster) at Carbondale and Edwardsville and dancer Katherine Dunham (Dunham, Katherine) at Edwardsville.