Ector /ˈɛktɔːr, -ər/, sometimes Hector, Antor, or Ectorius, is the father of Kay and the adoptive father of King Arthur in the Matter of Britain. Sometimes portrayed as a king instead of merely a lord, he has an estate in the country as well as properties in London.

Ector appears in the works of Robert de Boron and the Lancelot-Grail, as well as later adaptations such as the Post-Vulgate Cycle and Thomas Malory's Le Morte d'Arthur. In these versions, Merlin takes Arthur from his biological parents King Uther Pendragon and Igraine, and brings him to Ector's estate. Merlin does not reveal the boy's true identity, and Ector takes him on and raises him with Kay as his own son. When Kay is old enough to be knighted, Ector's young ward serves as his squire. In Malory's Le Morte d'Arthur, Ector also appears in the concluding book to recite a threnody lamenting Sir Lancelot's eventual death; however, the sole surviving manuscript of Mallory's work is missing the pages that would include this material, and at least one scholar has suggested that the speech may have been an addition by the text's printer, William Caxton.

In The Once and Future King T. H. White says his lands lie in the "Forest Sauvage"; some later writers have used this as well.

Mary Stewart's Arthurian Saga places Ector's estate in Galava, a fruitful land in Rheged inside the Wild Forest, south of Luguvalium and east of Glannoventa. Galava lies on a large lake with a central craggy island known as Caer Bannog, where 14-year-old Arthur finds and takes the sword which he names Caliburn. Stewart writes that the island is haunted (or guarded) by Bilis, a dwarf deity of the Otherworld and of underground spaces, rather than by the Lady of the Lake.

In the earlier Welsh stories, the father of Kay (Cei) is instead named Cynyr (Kyner).