ABSTRACTInteraction engagement is a critical yet under-explored aspect of learning engagement. Although some researchers have touched upon interaction engagement in English as a Foreign Language (EFL) contexts, few studies have discussed the influencing mechanism on it. Taking 352 Chinese college students as subjects, this study examined the relationship among EFL learners' perceived teacher emotional support, self-efficacy, and interaction engagement. It revealed that EFL learners' perceived teacher emotional support and self-efficacy predict interaction engagement. Besides, self-efficacy plays a mediating role between EFL learners' perceived teacher emotional support and interaction engagement. Based on the findings, this study suggests that teachers should enhance their emotional support, which will effectively increase students' self-efficacy, boost their interaction engagement, and thus improve their subjective well-being and academic performance.KEYWORDS: Interaction engagementteacher emotional supportself-efficacymediating effect AcknowledgmentsThe authors would like to thank the teachers and students for their cooperation.Disclosure statementNo potential conflict of interest was reported by the author(s).Ethical approvalThe current study was conducted upon approval from the institutional review board at the authors' universities. Informed consent was obtained from all the participants in the scope of the study.Additional informationFundingThis work was supported by The National Social Science Fund of China under grant number 16BYY092; The Scientific Research and Innovation Fund of Hangzhou Dianzi University for Postgraduates under grant number CXJJ2021022.