Following the paradigm shift in the area of language teaching from the previous teacher-centered methodologies towards learner-centeredness, attempts were made to bring up the learners who could take responsibility for their own learning. The ultimate goal of this new trend was to make language learners autonomous and independent in the process of language learning. Thus, new studies focused on investigating the characteristics of language learners in order to determine and highlight the characteristics of good language learners and make them available to other learners. The conducted explorations revealed that one of the areas in which good language learners were reported to excel other learners was known as language learning strategies (LLSs). These studies showed that instructing the appropriate strategies could enable language learners to process the language more efficiently and in the long run could lead to the development of communicative competence, enhanced proficiency, and autonomy in the learners. This caused many researchers to turn their interests to studies related to LLSs and to try to define theoretically this new concept.