| 4th Royal Irish Dragoon Guards | |
|---|---|
 Badge of the 4th Royal Irish Dragoon Guards | |
| Active | 1685–1922 |
| Country |  Kingdom of England (1685–1707)
 United Kingdom (1801–1922) |
| Branch |  British Army |
| Type | Cavalry |
| Role | Line Cavalry |
| Size | 1 Regiment |
| Nickname(s) | The Blue Horse, The Mounted Micks, The Buttermilks |
| Motto(s) | Quis separabit (Who shall separate us?) |
| March | Quick: St Patrick's Day Slow: 4th Dragoon Guards |
| Commanders | |
| Notable commanders | Lieutenant-General James Hamilton, 4th Duke of Hamilton Field Marshal James O'Hara, 2nd Baron Tyrawley |
The 4th Royal Irish Dragoon Guards was a cavalry regiment in the British Army, first raised in 1685 as the Earl of Arran's Regiment of Cuirassiers. It was renamed as the 4th (Royal Irish) Dragoon Guards in 1788 and service for two centuries, including the First World War, before being amalgamated with 7th Dragoon Guards (Princess Royal's), to form the 4th/7th Dragoon Guards in 1922.