| NAME | POSITION | SEASONS | COLLEGE |
|---|---|---|---|
| Obomanu, Ben | WR | 2013 | Auburn |
| O'Brien, Ken | QB | 1983-1992 | California-Davis |
| Ochi, Victor | LB | 2016 | Stony Brook |
| O'Connell, Kevin | QB | 2009, 2011 | San Diego State |
| O'Connor, Tom | P | 1987 | South Carolina |
| Odegard, Don | DB | 1990-1991 | Nevada-Las Vegas |
| O'Donnell, Neil | QB | 1996-1997 | Maryland |
| O'Dwyer, Matt | OG | 1995-1998 | Northwestern |
| Ogbogu, Eric | DE | 1998-2001 | Maryland |
| Ogbuehi, Cedric | OT | 2022 | Texas A&M |
| Oglesby, Alfred | DT | 1994-1995 | Houston |
| Ogletree, Alec | LB | 2020 | Georgia |
| Oldenburg, Clint | OT | 2007 | Colorado State |
| Olejniczak, Mark | QB | 1974 | Stevens Point, Wis |
| Oliver, Jeff | OT | 1989 | Boston College |
| Olson, Harold | QB | 1969 | Illinois State |
| O'Mahoney, Jim | LB | 1965-1967 | Miami |
| O'Neal, Steve | P | 1969-1972 | Texas A&M |
| O'Neill, Pat | K | 1995 | Syracuse |
| Onkotz, Dennis | LB | 1970-1971 | Penn State |
| Onwuasor, Patrick | LB | 2020 | Portland State |
| Osborne, Richard | TE | 1977 | Texas A&M |
| Osemele, Kelechi | OG | 2019 | Iowa State |
| O'Sullivan, Dennis | C | 1999, 2002 | Tulane |
| Owens, Burgess | DB | 1973-1979 | Miami |
| Owens, Henry | HB/SP | 1968 | Weber State |
| Owens, Marv | WR | 1975 | San Diego State |
| Owens, Mike | C | 1976 | Missouri |
| Owusu, Chris | WR | 2014-2015 | Stanford |
