Many experimental studies have reported factors affecting English listening comprehension in Korea. However the reported results do not specifically deal with how effective the factors are in improving English listening comprehension. This quantitative meta-analysis study, therefore, aims to investigate the effectiveness of the factors (vocabulary, sound discrimination, syntactic ability, background knowledge, and listening strategy) on the improvement of listening comprehension in Korean EFL classrooms. A total of 117 studies with 133 samples were collected, and their effect sizes (ES) were calculated based on Hedge’s g with the CMA software (ver. 2.2.056). The results of this study showed that syntactic ability had the greatest effect on listening comprehension (ES=.816, p=.012). Vocabulary learning (ES=.421), sound discrimination training (ES=.453), grammar education (ES=.816), activation of background knowledge (ES=.599), and listening strategy training (ES=.498) all contribute to effectively improving listening comprehension regardless of the age of Korean EFL learners. In addition, the length of listening instruction did not affect listening comprehension. Based on the findings, pedagogical suggestions are also discussed.
