| G/Capt | Group Captain |
| GA | Geologists' Association; Gaelic Athletic (Club); Georgia |
| GB | Great Britain, used chiefly of creations of titles of honour of |
| GBA | Governing Bodies Association |
| GBE | Knight or Dame Grand Cross, Order of the British Empire |
| GC | George Cross |
| GCB | Knight/Dame Grand Cross of the Order of the Bath |
| GCH | Knight Grand Cross, Hanoverian Order |
| GCIE | Knight Grand Commander, Order of the Indian Empire |
| GCLJ | Grand Cross, St Lazarus of Jerusalem |
| GCM | Gold Crown of Merit (Barbados) |
| GCMG | Knight or Dame Grand Cross, Order of St Michael and St George |
| GCSI | Knight Grand Commander of the Order of the Star of India |
| GCStJ | Bailiff or Dame Grand Cross, Most Venerable Order of the Hospital of St John of Jerusalem |
| GCVO | Knight or Dame Grand Cross, Royal Victorian Order |
| gdau | grand-daughter |
| GDC | General Dental Council |
| Gdn(s) | Garden(s) |
| GDR | German Democratic Republic |
| Gd(s) | Guard(s) |
| Gen | General |
| GER | Great Eastern Railway |
| gf | grandfather |
| ggdau | great-grand-daughter |
| ggf | great-grandfather |
| gggf | great-great-grandfather |
| ggggf | great-great-great-grandfather |
| gggs | great-great-grandson, etc |
| ggmother | great-grandmother |
| ggs | great-grandson |
| GGSM | Graduate in Music, Guildhall School of Music and Drama |
| GHQ | General Headquarters |
| Gib | Gibraltar |
| GIMechE | Graduate, Institution of Mechanical Engineers |
| GLC | Greater London Council |
| Glos | Gloucestershire |
| GM | George Medal; Grand Medal (Ghana) |
| GMB | (Union for) General, Municipal, Boilermakers |
| GMBATU | General, Municipal, Boilermakers and Allied Trades Union |
| GmbH | Gesellschaft mit beschrankter Haftung |
| GMC | General Medical Council; Guild of Memorial Craftsmen; General Management Course (Henley) |
| GMWU | General and Municipal Workers' Union |
| gn | great-nephew/-niece |
| Gns | Guineas |
| GOC | General Officer Commanding |
| Govr | Governor |
| Govt | Government |
| GP | General Practitioner; Grand Prix |
| GPDST | Girls' Public Day School Trust |
| GPMU | Graphical, Paper and Media Union |
| GPO | General Post Office |
| GR | General Reconaissance |
| Gren | Grenadier |
| GRSM | Graduate, Royal Schools of Music |
| GS | General Staff; Grammar School |
| GSM | General Service Medal; (Member of) Guildhall School of Music and Drama |
| GSO | General Staff Officer |
| Gt | Great |
| GWR | Great Western Railway |