| Surname | Forename | Rank | Unit | Born | Resided |
| MAPOTHER | William | Company Quartermaster Sergeant | Royal Inniskilling Fusiliers | Born Howth, Co. Dublin | |
| MARCHANT | Charles Stewart | Second Lieutenant | 5th Battalion, attached 9th Battalion, Royal Dublin Fusiliers | | |
| MARCHBANK | Francis William | Acting Sergeant | King's (Liverpool Regiment) | Born Dublin | Resided Dublin |
| MARCUS | Henry | Private | Royal Inniskilling Fusiliers | Born St. Mary's, Dublin | |
| MARKEY | Charles Aloysius | Sub-Lieutenant | Royal Navy Division | | |
| MARKEY | John | Private | Royal Dublin Fusiliers | Born Finglas, Co. Dublin | |
| MARKEY | John | Lance Corporal | Royal Dublin Fusiliers | Born Balbriggan, Co. Dublin | Resided Balbriggan |
| MARKEY | John Joseph | Private | Royal Dublin Fusiliers | Born Dublin | |
| MARKS | Victor Harold | Rifleman | London Regiment | | Teddington |
| MARLOW | James | Private | Royal Munster Fusiliers | Born St. John's, Dublin | Resided Dublin |
| MARNER | John | Private | Royal Army Medical Corps | Born Dublin | |
| MARRABLE | Francis Arthur | Sergeant | Royal Dublin Fusiliers | Born Kill, Co. Dublin | |
| MARSDEN | Harry | Rifleman | Royal Irish Rifles | Born Dublin | |
| MARSH | Albert J. | Private | Irish Guards | Born Dublin | Resided Dover, Kent |
| MARSH | Ernest Walker | Private | Royal Army Service Corps | Born Dublin | Resided Bagshot, Surrey |
| MARSHALL | George Patrick | Stoker 2nd Class | H.M.S. "Princess Irene" | | |
| MARSHALL | John | Sergeant | Loyal North Lancashire Regiment | Born Dublin | |
| MARSHALL | John | Private | Northumberland Fusiliers | Born Dublin | |
| MARSHALL | Arthur William | Corporal | Royal Fusiliers (City of London Regiment) | Born Basford | Resided Dublin |
| MARTIN | Charles Andrew | Captain | Royal Dublin Fusiliers | | |
| MARTIN | Alexander | Private | King's Own Scottish Borderers | Born Dublin | Resided Duns, Berwick |
| MARTIN | Charles | Lance Corporal | Princess Victoria's (Royal Irish Fusiliers) | Born Dublin | |
| MARTIN | Charles | Private | Royal Dublin Fusiliers | Born Lusk, Co. Dublin | Resided Lusk |
| MARTIN | Christopher Charles | Private | Princess Charlotte of Wales's (Royal Berkshire Regiment) | Born Dublin | Resided Southsea |
| MARTIN | Eric Franklin | Private | Machine Gun Corps | Born Dublin | Resided Lisburn, Belfast |
| MARTIN | Henry | Private | Royal Dublin Fusiliers | Born Dublin | |
| MARTIN | James | Private | Royal Dublin Fusiliers | Born Dublin | Resided Dublin |
| MARTIN | John | Private | Royal Irish Regiment | Born St. Thomas's, Dublin | |
| MARTIN | Joseph | Private | Royal Dublin Fusiliers | Born Terenure, Dublin | |
| MARTIN | Kevin | Private | Machine Gun Corps | Born Blackrock, Co. Dublin | |
| MARTIN | Lawrence Alfred | Lance Corporal | Oxfordshire and Buckinghamshire Light Infantry | Born Dublin | Resided New Bilton. Warwicks |
| MARTIN | Matthew | Private | Royal Inniskilling Fusiliers | Born Dublin | |
| MARTIN | Thomas | Private | South Wales Borderers | Born Kello, Dublin | |
| MARTIN | Thomas | Private | Connaught Rangers | Born Dublin | Resided Coolock |
| MARTIN | John | Acting Sergeant | Royal Horse Artillery and Royal Field Artillery | Native of Ireland | Resided Ringsend, Dublin |
| MARTIN | Richard Henry | Sergeant | Royal Irish Rifles | Born Fermoy, Co. Cork | Resided Dublin |
| MARTIN | Henry | Corporal | Buffs (East Kent Regiment) | Born St. Nicholas, Rochester, Kent | Resided Harolds Cross, Dublin |
| MARTIN | Edward | Gunner | Royal Garrison Artillery | Born Woolwich, Kent | Resided Dublin |
| MARTIN | B L | Lance Corporal | Leinster Regiment | | |
| MARTYR | John Francis | Captain | 1st Battalion, attached 6th Battalion, Royal Irish Rifles | | |
| MASON | John Norman | Lieutenant | 1st/1st, Dorset Yeomanry (Queen's Own) | | |
| MASON | George | Private (Acting Corporal) | Royal Irish Regiment | Born Sandyford, Dublin | Resided Sandyford |
| MASON | John | Rifleman | Royal Irish Rifles | Born Blackrock, Co. Dublin | Resided Blackrock, Co. Dublin |
| MASSEY | John J. | Private | Irish Guards | Born Dublin | |
| MASSEY | Leo | Private | Royal Dublin Fusiliers | Born Dublin | |
| MASSY-MILES | Harry Godfrey | Captain | Royal Army Medical Corps, attached 1st Battalion, London Regiment (Post Office Rifles) | Born at Dublin | |
| MASTERSON | Alfred | Private | Royal Dublin Fusiliers | Native of Kingstown, Co. Dublin | Resided Blackrock |
| MASTERSON | Andrew | Rifleman | Royal Irish Rifles | Born Dublin | Resided Belfast |
| MASTERSON | James | Private | Royal Dublin Fusiliers | Born Dublin | Resided Dublin |
| MASTERSON | Michael | Private | Royal Dublin Fusiliers | Born Dublin | |