AF
AF, af, Af, etc. may refer to:

Arts and entertainment
A-F Records, Pittsburgh, Pennsylvania
Almost Family, US TV series

Businesses and organizations
European
ÅF, a Swedish technical consulting company
AF Gruppen, a construction company, Norway
Action Française, a French political movement
Air France, IATA code and stock symbol
Anarchist Federation (British Isles)

International
Abercrombie & Fitch, A&F, US clothing shops
The Adaptation Fund, for climate change adaptation, UN
Adventist Forums, of Seventh-day Adventists

Elsewhere
American Freightways, US trucking company, merged into FedEx Freight

Language
Académie française, for French language matters
Alliance Française, promoting French language and cultureAcronym Finder, an online databaseAfrikaans language (ISO 639-1 language code AF)
"...as fuck", meaning "very", in SMS language

Military
AF Guardian, a US Navy warplane
Air force
Armed forces

Places
Afghanistan, by 2-letter ISO, FIPS 10-4 and obsolete NATO country code
.af, the top-level Internet domain for Afghanistan
Agra Fort railway station, Rawatpara,  India

Science and technology
Acoustics and communications
Amplify-and-Forward, a scheme of relay channel
Alternative frequency
Audio frequency

Units of measure
Acre-feet
Attofarad

Visual arts
Autofocus, of a camera
Anisotropic filtering

Other uses in science and technology
Af, the Köppen climate classification for a tropical rainforest climate
Across flats (A/F), a measure of hexagonal nut flat size
Advanced Format, large hard disk sectors
Anaerobic filter, a type of anaerobic digester
Arcuate fasciculus, a nerve bundle in the brain
Atrial fibrillation, an abnormal heart rhythm

Other uses
Alabama and Florida Railway (reporting mark AF)
Anno Fascista, a year in the Italian Fascist calendar