The current meta-synthesis study investigated the effect of critical thinking on the enhanced language learning, the most effective strategies on improving critical thinking ability among EFL/ESL learners, and the relationship between language learning skills and the improved critical thinking ability. To this aim, metasynthesis was seleced as the design of the study and some inclusion and exclusion criteria were determined. Given the meta-synthesis design of this study, some databases were searched using the defined key terms, in order to select the related qualitative, quantitative, and mixed-method studies. As a result, 550 articles were found, 50 articles of which were included in the final review. Using thematic analysis, the obtained data from these 50 articles were analyzed in 6 steps and then coded for each research question. The results of this study indicate that enhancing critical thinking can lead to the improved language learning from many aspects. Moreover, although no single method was proposed in this study as the best to improve critical thinking, it was indicated that a number of them can be effective when properly implemented. It was shown that all 4 language skills can definitely be improved by enhancing the level of critical thinking ability among EFL/ESL learners. Therefore, due to the findings of this review, critical thinking and the strategies to improve it should be included in the programs and curriculum designed for EFL/ESL learners to equip them with better language knowledge and enhance their language learning abilities. Furthermore, the findings of the present study might help students, teacher educators, administrators, policy makers, and teacher training courses (TTC) to improve students’ critical thinking ability for better learning.
