Self-efficacy (SE) plays an important function for a teacher in boosting teacherstudent engagement which may lead to positive outcomes. To investigate the different SE-related concerns among teachers, meta-analysis studies, systemic reviews, and many other sorts of studies in the field of education have been undertaken. In this study, an extended literature review was conducted to particularly investigate the issue of in-service EFL teachers' self-efficacy beliefs. To this end, using terms such as "self-efficacy in general teachers," "self-efficacy in EFL teachers," and "selfefficacy in language teachers," the researcher searched several important databases and found 31 relevant academic journal articles published over the past six years (2015-2021). These papers were derived from the following databases: Elsevier, Taylor & Francis Online, Wiley Online Library, Google Scholar, the JSTOR digital library, Education Source, ERIC (EBSCO), Sage Journal, Cambridge Core, Research Gate, and Research Online. This literature review reveals that research in this field is required to demonstrate how elements in the surroundings of teachers might predict changes in and build teacher self-efficacy beliefs. Additionally, this study is believed to have significant implications in understanding the need for research on selfefficacy via a complex dynamic system theory (CDST) perspective as well as an enhancement in the future of teachers' self-efficacy beliefs.