EF or ef may refer to:
Arts and entertainment Ef (band), a post-rock band from Sweden Ef: A Fairy Tale of the Two., a Japanese adult visual novel series by Minori, or its anime adaptations
Businesses and organizations Eagle Forum, an anti-feminist conservative interest group Earth First!, movement, in environmentalism Eastern Fare, a music institution and production house in Bangalore, India EF Education First, an international education organization The Elias Fund, a non-profit organization Far Eastern Air Transport (IATA code EF) Ethereum Foundation, Swiss non-profit foundation
Linguistics Ef (Cyrillic) (Ф, ф), a letter in the Cyrillic alphabet F (F, f), a letter in the Latin alphabet
Science Biology and psychology Ejection fraction, in cardiovascular physiology Elongation factors, proteins that are important in protein synthesis Executive functions, a theorized cognitive system in psychology that controls and manages other cognitive processes
Physics Electric field, in physics Exafarad, an SI unit of electric capacitance Fermi energy or Fermi level (EF), both concepts in quantum mechanics
Other sciences Ecological footprint, the measure of the demand the population has on the environment Enhanced Fujita scale (EF scale), an improved version of the Fujita scale used to rate the intensity of tornadoes Ice cap climate, which is abbreviated to EF in the Köppen climate classification
Technology Canon EF camera, a manual focus 35mm SLR Canon EF lens mount, Canon's autofocus lens mount Entity Framework, an object-relational mapping (ORM) framework for the .NET Framework
Other uses Extraordinary Form, a phrase used to describe the Catholic liturgy of the 1962 Roman Missal Era Fascista, the Italian fascist calendar Extra fine, a condition of a coin Eurofurence, a furry convention in Hamburg, Germany