The Ohio Athletic Conference (OAC) is an intercollegiate athletic conference which competes in the NCAA's Division III. All member institutions are located in Ohio. Formed in 1902, it is the third oldest athletic conference in the United States. In its history, 31 schools have been members of the OAC. The enrollments of the current nine member institutions range from around 1,000 to 4,500. Its current commissioner is Bethany Dannelly. Former commissioners include Mike Cleary, who was the first General Manager of a professional basketball team to hire an African American head coach, and would later run the National Association of Collegiate Directors of Athletics (NACDA).

The Ohio Athletic Conference was found in 1902 with six charter members—Case Tech, Kenyon, Oberlin, Ohio State, Ohio Wesleyan, and Western Reserve. By 1934, the conference reached an all-time high of twenty-four members, seeing many schools come and go throughout the upcoming decades. By 2000, the conference solidified to its current form with the addition of its final school, Wilmington, to ten members.

On January 18, 2024, John Carroll University announces departure from the OAC to the North Coast Athletic Conference (NCAC), beginning in the 2025–26 academic year.

The OAC currently has nine full members, all are private schools:

The OAC had 21 former full members, all but seven were private schools:

The OAC had three former associate members, all private schools. This included the only schools outside of Ohio that had any level of OAC membership.

 Full member (all sports)   Full member (non-football)   Associate member (football)   Associate member (sport) 

In 2023–24, the OAC sponsors the following championships: