EFL listening comprehension has been a stark challenge for language learners, but little is known about the combined effect of individual differences, such as working memory capacity, and metacognitive intervention. Thus, the present experimental study investigates the effect of metacognitive intervention on the listening performance and metacognitive awareness of high- and low-WMC EFL learners. For this purpose, Oxford Placement Tests were distributed among 120 male Iranian EFL learners, of which 94 were identified as intermediate. Then, backward visual digit span tests were administered to measure their working memory capacity. Based on the median of all scores, 80 learners were selected and randomly assigned to two experimental groups and two control groups each with 20 participants. Next, their performance on the International English Language Testing System and the Metacognitive Awareness Listening Questionnaire was measured before and after the 8-session metacognitive intervention. Results showed that high-WMC experimental learners had a higher gain with a large effect size in terms of listening performance compared with all the other groups. In addition, the experimental group learners reported the significantly higher use of the metacognitive strategies with a moderate effect size. Interestingly, low-WMC learners' listening performance and metacognitive awareness also improved as a result of the intervention. Our findings bear pedagogical significance in that individual differences in WMC should be considered more in both EFL language classes and the future line of research involving the metacognitive intervention.