This study explores the overall effectiveness of TETE in EFL Korean contexts. Through a comprehensive search on multiple electronic data bases, 28 primary studies were selected and 104 samples were coded into a CMA software to calculate effect sizes by computing Hedge’s g. The results of this meta-analysis showed an overall medium effect size on TETE for Korean L2 learners (ES=.369). TETE has medium effects in both cognitive (ES=.375) and affective (ES=.363) domains. However, there were no moderating effects (school levels, four language skills, and three affective factors). Research implications of the study and pedagogical suggestions are discussed.