Illinois State University is a public university in Normal, Illinois, United States. Most commonly referred to as ISU, the school was founded in 1857 by Jesse W. Fell (1808-1887); Abraham Lincoln drew up the legal documents to establish the university. The original name of the school was Illinois State Normal University, reflective of its primary mission to serve as a normal school for the training of teachers. In 1964, as the institution began expanding and moving toward a full liberal arts curriculum, its name was changed, first to Illinois State University at Normal, and then by 1968 to Illinois State University.

ISU is recognized by the US News rankings as a "National University", that is, a university which grants a variety of doctoral degrees and strongly emphasizes research. US News ranks ISU in the "third tier", meaning that it is currently in the third quartile of schools within the National University category. Among public universities in Illinois awarding doctorate degrees, only the University of Illinois at Urbana-Champaign ranks higher. It is also ranked as the 123rd best university in the U.S. by the Washington Monthly

The ISU athletic teams are members of the Missouri Valley Conference and the Missouri Valley Football Conference, and are known as the "Redbirds," in reference to the state bird, the cardinal.