- O'Brien, Brendan M.1
- O'Dowd, Sean K.1
- O'Keefe, Sean Crist1
- O'Neill, Brianne E.1
- O'Shea, Sean Michael1
- Olivieri, Steven J.1
- Olloqui, Fernando Miguel1
- Onoja, Augustine Abah1
- Orman, Neal C.2
- Orthodoxou, Demetra1
- Ossa Rodriguez, Daniel1
- Otalvaro-Gutierrez, Diana M1
- Oteri, Shannon L.1
- Ozden, Baran1
- Ozil, Ipek1