It is proven by many researchers that language learning strategies (LLSs) are very important in second/ foreign language learning and teaching and that learners might be able to learn second/ foreign language more effectively by using LLSs. That's why this area has increasingly received more attention during the past forty years. This paper is aimed to review previous research pertaining to language learning strategies (LLSs) to figure out the current directions of LLSs inquiry, especially in Vietnamese context, and propose directions for future studies on the field. 24 published journal articles and dissertations containing Vietnamese learners' LLSs were cautiously selected for "systematic reviews" that serve as the only tool for a source of data in this study. Findings uncovered that such research projects have addressed the call for considering self-regulation strategies; learning context and modern technology factors; and more mixed-methods approach. However, most of the Vietnamese researchers still adopt traditional definitions and classifications, and excessively use questionnaires for data collection. Also, that these studies principally focus on learners' use of strategies in their writing, listening or vocabulary learning provokes a lack of research on speaking learning strategies. Finally, results from these studies can not generalize other learner population of different contexts. The study suggests implications for further investigations into LLSs issues in prior research. Key words: English learning as a foreign language (EFL), language learning strategies (LLSs), self-regulated learning (SRL), language learning and teaching, language learning approaches