EFL is an acronym we use to talk about English as a Foreign Language.
EFL students are students learning English as a foreign language, that is, as a language other than their mother tongue or primary language. EFL students usually live in non English speaking countries and want to learn English mainly to use it on their travels or business trips abroad and to communicate with English speaking visitors to their country.
EFL programs are designed for all ages and school levels; from early childhood through to secondary school, to adults.
Compare this to ESL or English as a Second Language – this is what students who live in an English speaking country learn.
Teachers who teach EFL classes are defined as TEFL teachers as they Teach English as a Foreign Language, which is different from teaching English as a native language. To become a TEFL teacher you need specific teacher training.