MFO may refer to:

Organisations

* Maison Française d'Oxford, a French research institute based in Oxford, England * Multinational Force and Observers, an international peacekeeping force; or the related medal * Maschinenfabrik Oerlikon, a defunct Swiss manufacturing company, merged into Brown, Boveri & Cie in 1967 * Mathematisches Forschungsinstitut Oberwolfach (Mathematical Research Institute of Oberwolfach), in Germany * MrFixitOnline, a prominent gaming site focusing on online games, notably ''Age of Empires II: The Age of Kings'' that specialized in expert strategy and high caliber tournaments, in operation from ~2000 - 2006. * Multi-family office, organisations which protect and grow the wealth of several families by providing full growth and philanthropic investment advice.

Entertainment

* MFÖ, a Turkish band * My Family Online, a website/forum for hit BBC One sitcom, ''My Family''

Science

* In immunology, Multi Function Oxidase * Mixed-function oxidase

Other

* MFO, IATA airport code of Manguna Airport in Papua New Guinea * Marine Fuel Oil {{disambiguation