 What does TEFL mean? What does TESOL mean? The acronym TEFL stands for teaching English as a foreign language. TESOL is teaching English to speakers of other languages. Today, both terms have much the same meaning and are generally used interchangeably in the EFL field. In the early days, TEFL was more of a UK-based qualification and TESOL was more of a North American-based qualification. ESL is English as a second language and is usually used when teaching English in an English-speaking environment. Some people argue that TESOL encompasses both EFL and ESL. In reality, there is very little difference, if any. As the need for English language training has developed worldwide, the two terms have almost become synonymous. They are both used to describe the field of English language teaching and one of them is stated on your certification at the end of the course.