National Society of the 1917 World War Registrars
There are 1185 names on the list and 752 Gold Star Plaques were recovered.
The names in Bold
indicate that their Gold Star Plaque was recovered.
★ Indicates interment at Jefferson Barracks National Cemetery
| Last name | First name | Rank | Cause of Death | Year of Death | Theater | Unit | |
| O'Brien | Francis Roy | SEA APP | Died from disease | 1928 | USA | USN | |
| O'Brien | Leo P. | CPL | Killed in action | 1918 | AEF | 5TH REG (Marine) | |
| O'Connell | Dennis | PVT | Killed in action | 1918 | AEF | 355 INF | |
| O'Connell | William J. | PVT | Killed in action | 1918 | AEF | 138 INF | |
| O'Connors | John J. | PVT | Died from disease | 1923 | USA | SUP CO QMC | |
| O'Neil | Charles | 2ND LT | DA | 1919 | AEF | AS-SIG-C | |
| O'Neill | Laurence P. | DIED | 1918 | UNKN | 2 INF | ||
| Oberg | Emil Wm. | PVT | Killed in action | 1918 | AEF | 354 INF | |
| Obrinski | Florian | PVT | Killed in action | 1918 | AEF | 30 INF | |
| Oge | Roland B. | PVT | Died from disease | 1918 | USA | 38 ARTY CAC | |
| Ohren | Abraham | PVT | Killed in action | 1918 | AEF | 11 INF | |
| Oldham | Ralph D. | 1ST LT | Died from wounds | 1918 | AEF | 138 INF | |
| Oppenlander | Charles W. | Died from disease | 1918 | AEF | US MAR CORPS | ||
| Ostendorf | Edward H. | SGT MAJOR | Died from disease | 1918 | AEF | 2 INF | |
| Ostmeyer | Joseph | PVT | Killed in action | 1919 | AEF | 307 F SIG BN | |
| Overman | David R. | PVT | Killed in action | 1918 | AEF | MED CORPS | |
| ★ | Overman | John W. | Result of gas | 1926 | AEF | 128 FA | |
| Owens | Henry C. | CPL | Killed in action | 1918 | AEF | 138 INF |