'non-Anglo-Saxon' is formed from the negative prefix 'non-' plus 'Anglo-Saxon'. 'non-' originates from Latin 'non' meaning 'not'; 'Anglo' derives from the Angles (Old English/Latin), and 'Saxon' derives from the Saxons (Old English 'Seaxe' / Old Germanic 'Saxones').

'Anglo-Saxon' developed from references to the Angle and Saxon tribes in Old English and Latin; the compound 'Anglo-Saxon' entered Middle and Modern English to refer to the early medieval English people and their language. The modern English prefix 'non-' was later attached to form 'non-Anglo-Saxon' to mean 'not Anglo-Saxon'.

Initially, 'Anglo-Saxon' referred specifically to the historical peoples (the Angles and Saxons) and their language; over time it came to denote broader cultural or ethnic associations with early English identity. 'Non-Anglo-Saxon' thus evolved to mean 'not of Anglo-Saxon origin' in cultural, ethnic, linguistic, or historical contexts.