Saint Ælfflæd (654–713) was the daughter of King Oswiu of Northumbria and Eanflæd. She was abbess of Whitby Abbey from the death of her kinswoman Hilda in 680, first jointly with her mother, then alone.
Most of Ælfflæd's life was spent as a nun. When she was about a year old, her father, in thanksgiving for his victory over Penda of Mercia at the Battle of the Winwæd, handed her over to abbess Hilda to be brought up at Hartlepool Abbey. When Hilda left to found Whitby Abbey in 657 or 658, she brought Ælfflæd with her.
Like her mother, Ælfflæd was associated with Bishop Wilfrid, and played a large part in the settlement which placed her nephew Osred son of Aldfrith on the throne in 705. She was an important political figure from the death of her brother Ecgfrith in 685 until her death.
Her piety was praised by contemporaries such as Bede and Eddius. Bede refers to her high degree of holiness and devotion, while Eddius calls her the consoler of the whole kingdom and the best counsellor.
Ælfflæd was considered a saint and her feast day was celebrated on 8 February. She was buried at Whitby. A late hagiography, the Vita sanctae Elfledae, survives, collected in the Nova legenda Anglie of 1516.