- O'Shaughnessy Family Papers, 1857/19657
- O.D. Linder, Compiler, Genealogy Records Regarding the Boyce, Dever, Gibson, and Linder Families, 1860/2000, bulk 1900/20001
- O.J. Morrison Department Stores Company (West Virginia and Ohio) Records, 1910/1985, bulk 1940/19501
- O.W. Riegel Papers, 1900/19921,110
- Oak Grove Baptist Church collection, 1924/19452
- Obituaries of Ritchie and Tyler County Residents, 1947/20141
- Ocean View, Seaside, and Seaview Amusement Parks Collection, 1919/1991, bulk 1940/197938
- Office of Admission records, 1861/20217
- Office of Alumni Engagement records3
- Office of Alumni Relations Records, 1960/201857
- Office of Communications and Marketing audio and video collections1
- Office of Communications and Marketing subject files, 1950235
- Office of Communications and Public Affairs records, 1948/2002125
- Office of Educational Media, 1947/19842
- Office of Grants and Research Administration Records, 1960/1994, bulk 1960/19942