'self-identification' is a compound of 'self' (Old English 'self', meaning 'one's own; the same') and 'identification' (from Late Latin 'identificare' via French 'identifier'). In 'identificare', the element 'ident-' comes from Latin 'idem' meaning 'same', and '-ficare' from Latin 'facere' meaning 'to make'.

'identificare' (Late Latin) became Old French 'identifier' and then entered English as 'identify' in Middle English; the noun 'identification' developed from this verb. The modern compound 'self-identification' arose by combining 'self' with 'identification' to specify identifying oneself.

Originally related to making or showing that two things are the same ('to make the same'), the sense shifted toward recognizing, establishing, or declaring identity; in modern usage it commonly denotes the act of a person identifying themselves.