| Name | Place born | Place enlisted | Residence | No. | Rank | Former unit | How died | Theatre | Date |
|---|---|---|---|---|---|---|---|---|---|
| Oldfield, Edgar | Halifax, Yorkshire | Halifax | 33563 | Pte. | k.i.a. | F & F | 10 July 1917 | ||
| Oliphant, Joseph | Wigton, Cumberland | Wigton | Oulton, Cumberland | 241653 | Pte. | k.i.a. | F & F | 12 March 1918 | |
| Oliphant, Thomas | Abbeytown, Cumberland | Penrith, Cumberland | 28150 | Pte. | k.i.a. | F & F | 2 December 1917 | ||
| Osborn, John Barwise | Allonby, Cumberland | Aspatria, Cumberland | Bootle, Cumberland | 19691 | Pte. | d. | F & F | 31 May 1916 | |
| Osborne, George Henry | Denbury, Devon | Newton Abbot, Devon | Holne, nr. Ashburton, Devon | 33522 | Pte. | (116946 Royal Garrison Artillery | d.o.w. | F & F | 11 July 1917 |
| Osborne, William | Glasgow, Lanarkshire | Keswick, Cumberland | Larbert, Stirlingshire | 13583 | Pte. | k.i.a. | F & F | 2 October 1918 | |
| Ousby, Walter | Penrith, Cumberland | Penrith | 27995 | Pte. | d. | F & F | 13 January 1917 | ||
| Owens, David Evan | Betws-y-Coed, Caernarfonshire | Hereford, Herefordshire | Ledbury, Herefordshire | 27684 | Pte. | (2624) Herefordshire Regiment | k.i.a. | F & F | 18 November 1916 |
| Owens, John James | Seaton, Cumberland | Workington, Cumberland | 16435 | Sgt. | k.i.a. | F & F | 10 July 1917 |