Former Owner
- Nīlakaṇṭha Tanūja1
- Nūr al-Dīn Darvīsh2
- O. A. Bump1
- Ochsenhausen Abbey1
- Octave Chavaillor1
- Oettingen-Wallerstein library1
- Offley Bohun Stovin Fairless Shore1
- Ohio State University Center for Epigraphical and Palaeographical Studies1
- Ohio State University School of Music1
- Okar, Baganbhaṭṭa1
- Oliver Henry Perkins13
- Oliver R. Barrett4
- Omaha Public Library1
- On inside front cover: "Graf v. Villers von Burges<?>, 1817" in ink; "London [Lauden?] 21535x" in pencil; "Douanes Paris Exposition" on a faded round pink sticker. "Memorandum from the Johnson Library" note inside book.1
- Oric Bates2
- Orlandus de Fatiis1
- Oswald Carl Friedrich von Seilern und Aspang2
- Otto Ege125
- Otto Haas1
- Otto Jahn1