MEI
- 4-Methylimidazole
- Energy Institute
- Intel Active Management Technology
- Iodomethane
- MEI (company)
- MEI Academy
- MEI Hellhound (Grenade)
- MEI Mercury
- Marginal efficiency of investment
- Mathematics in Education and Industry
- Matsushita Electric Industrial Co., Ltd.
- Media and Entertainment International
- Medicare Economic Index
- Mei (disambiguation)
- Mennonite Educational Institute
- Meridian (Amtrak station)
- Meridian Regional Airport
- Merit, excellence, and intelligence
- Middle East Institute
- Middle East International
- Ministry of Economy and Innovation
- Montreal Economic Institute
- Multivariate ENSO index
- Music Encoding Initiative
- OECD Main Economic Indicators