SEF explained

SEF may refer to:

Sankara Eye Foundation, a non-profit that works for eradicating curable blindness in India
Serviço de Estrangeiros e Fronteiras, Portuguese Border and Alien Service
Sinfonia Educational Foundation, the philanthropic arm of the Phi Mu Alpha Sinfonia Music Fraternity
Small Enterprise Foundation, a microfinance institution operating primarily in the Limpopo province of South Africa
South Eastern Freeway, a Freeway in Australia
Special Emergency Force, A Saudi Arabian riot control and counter-terrorism force
Spectral edge frequency, a measure used in signal processing
Stadio Erinis & Filias, the Greek name for Peace and Friendship Stadium, an indoor sports arena in Athens
Straits Exchange Foundation, a semi-official organization of Taiwan that deals with the business matters with China
Supplementary eye fields, areas in the primate brain that are involved in planning and control of saccadic eye movements
Swap Execution Facility, a platform for regulated trading and clearing of swaps to be required in the United States by the Dodd-Frank bill
Swedish Elite Football
Swedish Electricians' Union, a trade union in Sweden
Seaford railway station (England), a railway station in Sussex, England