| O'Brien | Robert | 431 | Private | Source: OZ-Boer database | Queensland, 7th Battalion Australian Commonwealth |
| O'Brien | S | | | Source: QSA and KSA medal rolls | 42nd Battery, RFA |
| O'Brien | S | 72019 | Driver | QSA (1) DoL
Provisional list of recipients
Source: Ladysmith Siege Account and Medal Roll | 42nd Battery, RFA |
| O'Brien | S | | | 6th Battalion
Source: QSA and KSA medal rolls | Lancashire Fusiliers |
| O'Brien | S | | | Source: WO100/146 | No 10 Mountain Battery, RGA |
| O'Brien | S | 6415 | Sergeant | 6th Battalion
Source: QSA roll | Lancashire Fusiliers |
| O'Brien | S | | | Source: QSA and KSA medal rolls | No 10 Mountain Battery, RGA |
| O'Brien | S | 72019 | Driver | QSA (5) CC DoL OFS LN Belf
Provisional list of recipients
Source: Ladysmith Siege Account and Medal Roll | A Battery, RHA |
| O'Brien | S | 98297 | Gunner | Missing - released at Nicholson's Nek. 30 Oct 1899.
Source: Natal Field Force Casualty Roll, page 29 line 21 | No 10 Mountain Battery, RGA |
| O'Brien | S F | 801 | Trooper | Source: Nominal roll in WO127 | Johannesburg Mounted Rifles |
| O'Brien | Samuel | 437 and 4053 | Trooper | Source: Nominal roll in WO127 | Western Light Horse |
| O'Brien | Summer Wellesley | 7088 | | Source: Medal rolls | Canada, 2nd Royal Canadian Regiment of Infantry |
| O'Brien | T | 3377 | Private | QSA (3). Alias ' J. McGrath'. Prisoner, near Derdepoort, 11 Jul 00. Released.
Source: QSA medal rolls | 7th (The Princess Royal's) Dragoon Guards |
| O'Brien | T | | | 6th Battalion
Source: QSA and KSA medal rolls | Lancashire Fusiliers |
| O'Brien | T | | | 2nd Battalion
Source: QSA and KSA medal rolls | Royal Scots Fusiliers |
|
|
