A Mii is a personalized digital avatar for Nintendo's Wii and Nintendo 3DS video game consoles.
Mii, or MII, may also refer to:
- 1002, the year or the number, in Roman numerals
- Major Industry Identifier, part of ISO/IEC 7812
- Maritime Institute of Ireland, who operate the National Maritime Museum of Ireland
- Media Independent Interface, in Ethernet hardware
- Medium Independent Interface, in the ITU-T G.hn standard for high-speed networking over home wires
- MII, cost estimating software developed for the United States Army Corps of Engineers by Project Time & Cost, Inc.
- MII (videocassette format), a professional video tape format developed by Panasonic
- Cyrix 6x86, an x86 architecture CPU by Cyrix also known as "MII"
- Mineral Information Institute, an American educational institute dedicated to teaching schoolchildren about natural resources
- Ministry of Information Industry of the People's Republic of China, a former ministry of the State Council of the People's Republic of China, precursor to the MIIT
- Mutual Information Index
- Mii (Jungle de Ikou!), the busty Goddess of Fertility in Jungle de Ikou!
- Mii, one of the main characters from Popotan
- SEAT Mii, a small car by SEAT