The Ohio State University, commonly called Ohio State or OSU, is a public land-grant research university in Columbus, Ohio. A member of the University System of Ohio, Ohio State was founded in 1870 as the state's land-grant university and the ninth university in Ohio with the Morrill Act of 1862. Ohio State was originally known as the Ohio Agricultural and Mechanical College and focused on various agricultural and mechanical disciplines, but it developed into a comprehensive university under the direction of then-Governor and later U.S. president Rutherford B. Hayes, and in 1878, the Ohio General Assembly passed a law changing the name to "the Ohio State University" and broadening the scope of the university. Admission standards tightened and became greatly more selective throughout the 2000s and 2010s. As of 2021, Ohio State has the most students in the 95th percentile or above on standardized testing of any public university in the United States. It is classified among "R1: Doctoral Universities – Very high research activity". The university's endowment of $7.0 billion in 2022 is among the largest in the world.

A member of the Association of American Universities, Ohio State is a leading producer of Fulbright Scholars. Past and present alumni and faculty include five Nobel Prize laureates, nine Rhodes Scholars, seven Churchill Scholars, one Fields Medalist, seven Pulitzer Prize winners, 64 Goldwater scholars, seven U.S. Senators, 15 U.S. Representatives, and 108 Olympic medalists. Ohio State's faculty currently includes 21 members of the National Academy of Sciences or National Academy of Engineering, four members of the National Academy of Medicine and 177 elected fellows of the American Association for the Advancement of Science. Each year since 2002, Ohio State has either led or been second among all American universities in the number of their faculty members elected as fellows to the AAAS.

The university has an extensive student life program, with over 1,000 student organizations; intercollegiate, club and recreational sports programs; student media organizations and publications, fraternities and sororities; and three student governments. Its athletic teams compete in Division I of the NCAA and are known as the Ohio State Buckeyes, and it is a member of the Big Ten Conference for the majority of its sports. The school's football program has had great success and is one of the major programs of college football; their rivalry against the University of Michigan has been termed as one of the greatest in North American sports. As of 2017, Ohio State's football program is valued at $1.5 billion, the highest valuation of any such program in the country. The main campus in Columbus has grown into the third-largest university campus by enrollment in the United States, with nearly 50,000 undergraduate students and nearly 15,000 graduate students.