This qualitative research explores the conceptions, implementation and challenges of critical thinking in the FL classroom. 24 Libyan EFL university instructors participated in this study though completing an open-ended questionnaire sent via FB messenger. The content analysis applied to the participants’ answers revealed different conceptions and misconceptions of critical thinking. It also revealed that the majority of the participants implemented critical thinking in different aspects of their teaching. Some social, cultural and administrative barriers limited the effectiveness of this implementation. Nevertheless, the development of this kind of thinking for 21-century EFL learners is a necessity, not an option.