Mountjoy Prison
| View of the prison from North Circular Road | |
| Location | 
 | 
|---|---|
| Coordinates | 53°21′42″N 06°16′03″W / 53.36167°N 6.26750°W | 
| Status | Operational | 
| Security class | Medium security | 
| Capacity | 570 | 
| Population | 550 (as of 2015) | 
| Opened | 1850 | 
| Managed by | Irish Prison Service | 
| Governor | Ray Murtagh | 
Mountjoy Prison (Irish: Príosún Mhuinseo), founded as Mountjoy Gaol and nicknamed The Joy, is a medium security men's prison located in Phibsborough in the centre of Dublin, Ireland. The current prison Governor is Ray Murtagh.