There are 24 mathematicians whose last name begin with OI.
| Oi, Daniel | University of Oxford | 2002 |
| Oi, Hitoshi | University of South Florida | 2000 |
| Oi, Masao | Kyoto University | 2014 |
| Oi, Masao | University of Tokyo | 2019 |
| Oi, Shiho | Niigata University | 2020 |
| Oi, Walter | The University of Chicago | 1961 |
| Oidtman, Rachel | University of Notre Dame | 2021 |
| Øien, Alf | ||
| Oikari, Tuomas | Helsingin yliopisto | 2022 |
| Oikarinen, Joona | Helsingin yliopisto | 2022 |
| Oikawa, Issei | University of Tokyo | 2012 |
| Oikawa, Kotaro | University of California, Los Angeles | 1958 |
| Oikawa, Mizuki | University of Tokyo | 2024 |
| Oikhberg, Timur | Texas A&M University | 1999 |
| Oikkonen, Juha | Helsingin yliopisto | 1979 |
| Oikonomopoulos, Antonios | Imperial College London | 2010 |
| Oikonomopoulos, Dimitrios | Rheinische Friedrich-Wilhelms-Universität Bonn | 2019 |
| Oinarov, Ryskul | Institute Mathematics Acad. of Science, Kazakhstan | 1994 |
| Öinert, Johan | Lund University | 2009 |
| Oishi, Cassio | Universidade de São Paulo | 2008 |
| Oishi, Meeko | Stanford University | 2004 |
| Oita, Marilena | Télécom ParisTech | 2012 |
| Oitavem, Isabel Maria | Universidade de Lisboa | 2001 |
| Oitmaa, Jaan |