Deyn is from Littleborough in Lancashire. Deyn later moved to Failsworth near Oldham. The daughter of a nurse, Lorraine, and second of three children she moved to Rossendale, Lancashire, and attended All Saints Roman Catholic High School, as well as Bacup and Rawtenstall Grammar School and Sixth Form in Waterfoot, Rossendale.
Deyn's name was apparently coined to further her modelling career after she consulted her mother's friend, a numerology expert who advised her of the most 'fortuitous' way to spell the name 'Agnes'. It was reported that her mother Lorraine and sister Emily have Read his whole biography