First Battalion Four Marines
Personnel Rosters
1 January - 31 December 1968
| Name | Rank | MOS | Company | Tour | Purple Heart | Purple Heart | Purple Heart | KIA |
| Oakes, Ronald G | Cpl | 0311/0141 | A/HS | 9 Sep 68 | ||||
| Oberg, John R | PFC | 0341 | HS | 19 Jul 68 | ||||
| O'Brien, Alan G | L/Cpl | 2531 | HS | 5 Sep 68 | ||||
| O'Brien, Robert J | L/Cpl | 0311 | HS | 10 Nov 68 | ||||
| O'Connell, Bartholomew | L/Cpl | 0311 | A | 18 Aug 68 | ||||
| Ogden, Dudley J M | Sgt | 0331 | A | 27 Oct 67 | ||||
| Ollar, David L | Sgt | 0231 | HS | 2 Nov 67 | 23 Dec 67 | |||
| Olsen, Dale B | 1st Lt | 7521 | HS | 24 Apr 67 | ||||
| Olson, Fred W | PFC | 3371 | HS | 24 Aug 68 | ||||
| Olson, Richard James | PFC | 0311 | D | 22 Oct 67 | 26 Apr 68 | |||
| O'Mahoney, Terrence E | L/Cpl | 0141 | HS | 16 May 68 | ||||
| O'Neill, James M | Cpl | 2511 | HS | 4 Mar 68 | ||||
| O'Neill, John E | MAJ | 0302/3502/0130 | HS | 4 Mar 68 | ||||
| Ormsbee, Bruce J | PFC | 0351 | HS | 19 Jul 68 | ||||
| Ortiz, Santos J | PFC | 0341 | HS | 22 Dec 68 | ||||
| Osborn, James Q | Cpl | 3371 | HS | |||||
| Osborne, Leonard | Cpl | 0311/0846 | A | 6 Dec 67 | ||||
| Ostertag, Donald J | L/Cpl | 0351 | D | |||||
| Otten, Thomas L | PFC | 0341 | D | |||||
| Overton, Jon A | Cpl | 0351 | A | 10 Apr 67 | ||||