There are 30 mathematicians whose last name begin with ORR.
| Orr, Craig | Temple University | 1994 |
| Orr, Dalton | Tulane University | 1977 |
| Orr, Daniel | The University of North Carolina at Chapel Hill | 2013 |
| Orr, Derek | University of Pittsburgh | 2021 |
| Orr, Genevieve | Oregon Graduate Institute of Science & Technology | 1995 |
| Orr, George | Tulane University | 1971 |
| Orr, Gilbert | University of Miami | 1973 |
| Orr, H. Allen | The University of Chicago | 1990 |
| Orr, John | University of London | 1989 |
| Orr, Kent | Rutgers University, New Brunswick | 1985 |
| Orr, Larry | Massachusetts Institute of Technology | 1967 |
| Orr, Martin | Université Paris-Sud XI - Orsay | 2013 |
| Orr, Megan | Iowa State University | 2012 |
| Orr, Richard | Syracuse University | 1969 |
| Orr, Robert | Imperial College London | 1973 |
| Orr, Tony | University of Glasgow | 1996 |
| Orr, William | University of Wisconsin-Madison | 1973 |
| Orrala Poveda, Carlos | Claremont Graduate University | 2004 |
| Orre, Ronald | Kungliga Tekniska Högskolan (KTH) | 2003 |
| Orrick, William | State University of New York at Stony Brook | 1997 |
| Orrieri, Carlo | Università degli Studi di Pavia | 2015 |
| Orrill, Chandra | Indiana University | 1999 |
| Orrillo, Jaime | Instituto de Matemática Pura e Aplicada | 1999 |
| Orriols, Antonin | École Nationale des Ponts et Chaussées | 2006 |
| Orrison, Jr., Michael | Dartmouth College | 2001 |
| Orrit, Michel | ||
| Orro, Patrice | Université de Paris | 1984 |
| Orru, Romano | Landbouwuniversiteit Wageningen | 1994 |
| Orrù, Michele | École Normale Supérieure | 2020 |
| Orrù, Nicola | Università di Pisa | 1992 |