The University of Wisconsin–Madison (University of Wisconsin, Wisconsin, UW, UW–Madison, or simply Madison) is a public land-grant research university in Madison, Wisconsin, United States. It was founded in 1848 when Wisconsin achieved statehood and is the flagship campus of the University of Wisconsin System. The 933-acre (378 ha) main campus is located on the shores of Lake Mendota; the university also owns and operates a 1,200-acre (486 ha) arboretum 4 miles (6.4 km) south of the main campus.

UW–Madison is organized into 13 schools and colleges, which enrolled approximately 34,200 undergraduate and 14,300 graduate and professional students in 2024. Its academic programs include 136 undergraduate majors, 148 master's degree programs, and 120 doctoral programs. Wisconsin is one of the founding members of the Association of American Universities and is classified among "R1: Doctoral Universities – Very High Research Activity". UW–Madison was also the home of both the prominent "Wisconsin School" of economics and diplomatic history. It ranked sixth among U.S. universities in research expenditures in 2023, according to the National Science Foundation.

As of March 2023, 20 Nobel laureates, 41 Pulitzer Prize winners, 2 Fields medalists, and 1 Turing Award recipient have been affiliated with UW–Madison as alumni, faculty, or researchers. It is also a leading producer of Fulbright Scholars and MacArthur Fellows. The Wisconsin Badgers compete in 25 intercollegiate sports in NCAA Division I, primarily in the Big Ten Conference, and have won 31 national championships. Wisconsin students and alumni have won 50 Olympic medals (including 13 gold medals).