- Oberling, Antonia
- Obermark, Jonas Paul
- Obermark, Louisa Marie
- Obersteller, Axel Fabian
- Obersteller, Miriam Diana
- Ociepka, Isabella-Lara
- Oconnor, Francesca
- Ode, Sebastian
- Ode, Steven
- Oehl, Benedikt
- Oeler, Moritz
- Oeltjenbruns, Lea Pascal
- Oertel, Annabel
- Oertel, Annabell
- Oertel, Florentien
- Oertelt, Celine
- Oesterreich, Franz
- Oestreich, Denise
- Oettert, Lucas
- Oezbeck, Jonathan-Can
- Oeztürk, Sonnele
- Offermanns, Tim
- Ohashi, Yui
- Ohlschmid, Luna
- Okrema, Christian
- Okrema, Patrick
- Okwuchi, Yanek Uzochi
- Olbrich, Jonas
- Olbrich, Tim
- Oldenburg, Anja
- Oldenburg, Lucas
- Oleksiak, Penny
- Oliverio, Alessandro
- Olivier, Monique
- Olsen, Elise Naess