MFI may refer to:
- Made for iPhone/iPod/iPad, Apple's licensing and certification program for electronic accessories that connects with their portable devices.
- Magnetic field imaging, a non invasive and contact free cardiac diagnostic method
- Malmö Flygindustri, see Saab MFI13 and MFI-9 Junior
- Media Factory, Inc., an anime company
- Melt flow index, a characteristic property of a thermoplastic polymer as a means of quality control
- Messiah Foundation International the spiritualist organization
- MFI Foundation Inc., a non-stock, non-profit science foundation providing technical-vocational scholarship and training in the Philippines
- MFI Group, a former British high street furniture retailer, now an online store
- Microfinance institution, an alternate form of bank found in developing countries which provides microcredit lending
- Micromechanical Flying Insect
- Mikoyan Project 1.44, MiG-MFI, a Russian aircraft under development
- MindFreedom International, an advocacy coalition dedicated to championing the rights of people labeled with psychiatric disorders
- Minimum Fisher information, a variational principle in information theory
- Ministers Fellowship International, a fellowship of non-denominational charismatic churches, a theologically mainstream descendant of the Latter Rain (post–World War II movement)
- Modus Furniture International, Inc., a Furniture Manufacturer
- Money flow index, a technical analysis indicator
- Multi-port fuel injection
- Multilateral Financial Institutions
- Myfreeimplants a social networking website that offers an alternative to cosmetic surgery financing via online contributions from its members.
- Mean Fluorescence Intensity