Donnchad Donn
| Donnchad Donn | |
|---|---|
| High King of Ireland | |
| Reign | 919–944 |
| Predecessor | Niall Glúndub |
| Successor | Congalach Cnogba |
| King of Mide | |
| Reign | 919–944 |
| Predecessor | Conchobar mac Flainn |
| Successor | Oengus mac Donnchada |
| Died | 944 |
| Spouse |
|
| Issue |
|
| House | Clann Cholmáin |
| Father | High King Flann Sinna |
| Mother | Gormlaith ingen Flann mac Conaing |
Donnchad Donn mac Flainn (Duncan of the Brown Hair, son of Flann) (died 944) was High King of Ireland and King of Mide. He belonged to Clann Cholmáin, a branch of the southern Uí Néill.