- Marriage (1): Angharad Ferch Llewelyn
- Died: 987
Owain ap Hywel (died 987) was king of Deheubarth in south Wales and probably also controlled Powys.
Owain was the son of Hywel Dda, originally king of Deheubarth but by the end of his life king of most of Wales. On Hywel's death in 950 Deheubarth was shared between Owain and his two brothers, Rhodri and Edwin. The sons of Hywel were not able to keep hold of Gwynedd, which was reclaimed for the traditional dynasty of Aberffraw by Iago ap Idwal and Ieuaf ap Idwal, the sons of Idwal Foel.
In 952 Iago and Ieuaf invaded the south, penetrating as far as Dyfed. The sons of Hywel retaliated by invading the north in 954, reaching as far north as the Conwy valley before being defeated in a battle at Llanrwst and being obliged to retreat to Ceredigion.
Rhodri died in 953 and Edwin in 954, leaving Owain to rule Deheubarth alone. Owain did not again try to reclaim Gwynedd, but instead he and his son Einon turned eastwards to attack the kingdom of Morgannwg (modern Glamorgan) in 960, 970 and 977. Owain was now ageing, and it appears that Einon took over the rule of the kingdom on behalf of his father. On a further raid on the east in 984, Einon was killed by the noblemen of Gwent.
Following Einon's death, Owain's second son, Maredudd, took over the leadership in war, and in 986 did what his father had failed to do by seizing the throne of Gwynedd, ousting Ieuaf's son Cadwallon ab Ieuaf. The following year Owain died and Maredudd became king of Deheubarth as well as Gwynedd.
The Annales Cambriae were compiled at Owain's instigation
Noted events in his life were:
• He worked as a King of S. Wales.
Owain married Angharad Ferch Llewelyn.