'pro-regime' originates from Latin and French: specifically the Latin prefix 'pro' (via English), meaning 'for' or 'in favor of', and the French word 'régime' (from Latin 'regimen'), meaning 'rule' or 'government'.

'pro-regime' developed as a modern English compound combining the prefix 'pro-' (used in English from Latin 'pro') with 'regime' (borrowed into English from French 'régime', itself from Latin 'regimen'); compounds such as 'pro-government' appeared in the 19th–20th centuries and 'pro-regime' became common in political reporting in the 20th century.

Initially it literally meant 'for the regime'; over time the phrase has retained that core sense while becoming a concise political label for supportive individuals, groups, or actions.