MIA is a three-letter acronym that is most commonly used to designate a combatant who is Missing In Action, and has not yet returned or otherwise been accounted for as either dead (KIA) or a prisoner of war (POW).

The abbreviation can also refer to the following:

• Miami International Airport
• Meat Inspection Act
• Meetings Industry Association
• Mobile Internet Access
• Monthly Income Allowance
• Motorsport Industry Association
• Multivendor Integration Architecture
• Music Industries Association
• London-based singer M.I.A.