'mythologize' originates from Greek, specifically the word 'mythos' (Greek 'μῦθος'), where 'mythos' meant 'story' or 'speech', combined with the Greek element 'logia' (from 'logos') as in 'mythology', and the suffix '-ize' (via Late Latin/French) meaning 'to make' or 'to render'.

'mythologize' developed from the noun 'mythology' (from Greek 'mythologia' via Latin and Middle French) with the addition of the verb-forming suffix '-ize' in Modern English, producing the verb meaning 'to make into myth' or 'to treat as legendary'.

Initially, formations from 'myth-' plus '-ize' meant 'to turn into myth' or 'to tell as myth'; over time the verb and its past forms broadened to include figurative senses such as 'to idealize', 'to glorify', or 'to exaggerate qualities', while retaining the core sense of treating as legendary.