MSIA can refer to
- MSIA, an acronym for Mass Spectrometric Immunoassay, protein analysis
- MSIA, an acronym for Master of Science in Industrial Administration, a graduate degree.
- MSIA, an acronym for Master of Science in Information Assurance, a graduate degree.
- MSIA, an acronym for the Movement of Spiritual Inner Awareness, an American new religious movement.
- MSIA, an acronym for Mobile Suit In Action, a line of Gundam action figures made by Bandai
- Msia, an abbreviation for Malaysia
- Msia (ward), an administrative ward in the Mbozi District of Tanzania