O
- O'Connell, Caolionn
- O'Donoughue, Nicholas A.
- O'Hanlon, Claire E.
- O'Hollaren, Kelsey
- O'Mahony, Angela
- Ober, Allison J.
- Ochmanek, David
- Ogden, Theodora
- Ohana, Elie
- Ohlandt, Chad J. R.
- Okeke, Edward N.
- Okuda-Lim, Zhan
- Olmsted, Stuart S.
- Opfer, V. Darleen
- Opper, Isaac M.
- Orr, Scott
- Orvis, Bruce R.
- Osburg, Jan
- Osoba, Osonde A.