Der-Ilei (floruit late 7th century) is believed to have been a daughter, or less probably a sister, of Bridei map Beli, king of the Picts (died 693). There are no explicit mentions of Der-Ilei in the Irish annals or other sources, and her existence and parentage are thus based on the implication of the surviving records.
Der-Ilei is presumed to have been married to Dargart mac Finguine (died 686), a prince of the Cenél Comgaill. Their children are thought to have included Bruide mac Der-Ilei (died 706) and Nechtan mac Der-Ilei (died 732), kings of the Picts, and perhaps the Comgal mac Dargarto whose death in 712 is noticed by the Annals of Ulster.
She also married a man named Drostan—the hypocoristic form of the common name Drest or Drust—with whom she had a son named Talorc or Talorcan—Talorcan, again, is a hypocoristic form. Drostan and Der-Ilei may have been the parents of Finguine, killed in 729 with his son Feroth at the battle of Monith Carno, or he may have been a son of Drostan by another marriage.
It is not clear which of these marriages produced Der-Ilei's son Ciniod (died 713).
Since Bruide son of Dargart was evidently an adult in 696, and Talorc son of Drostan does not appear in the record until 713, it is thought that Der-Ilei married Drostan following the death of Dargart.
- Anderson, M. O. (1980), Kings and Kingship in Early Scotland (2nd ed.), Edinburgh: Scottish Academic Press, ISBN 0-7011-1604-8
- Clancy, Thomas Owen (2004), "Philosopher-King: Nechtan mac Der-Ilei", Scottish Historical Review (Edinburgh: Edinburgh University Press) 83 (2): 125–149, doi:10.3366/shr.2004.83.2.125, ISSN 0036-9241