Although these two acronyms have been known to cause confusion in some situations, they are typically used to refer to the same thing.
TEFL = Teaching English as a Foreign Language
TESOL = Teaching English to Speakers of Other Languages
Do different countries prefer TEFL or TESOL?
While you might hear either acronym used in any given situation, it is generally the case that TEFL is used more in the UK and TESOL is more often used in North America and Australia. Despite the fact that one country might prefer one acronym over the other, it is worth remembering that a TEFL and a TESOL qualification are essentially the same thing as they follow identical curriculums.
Are TEFL and TESOL technically different?
Although it is true that a TEFL course and a TESOL course are identical and the respective acronyms are used interchangeably, it is also true that there are technical differences between the two. If you are teaching English in a non-English speaking country this would be considered Teaching English as a Foreign Language (TEFL) as your students do not need to speak English in their everyday lives but are learning it for another reason such as travel, work or even as a hobby. In contrast, teaching English in an English speaking country would be considered Teaching English to Speakers of Other Languages (TESOL) as your students are likely to need the language for everyday use such as shopping, socializing and in the workplace.