This study intends to demonstrate a detailed knowledge map of language teachers' self-efficacy research via the past 20 years' data from the Web of Science (WoS) database. A bibliometric analysis was employed to analyze the articles published between 2003 and March 2023 to show the status of language teachers' self-efficacy research in the last two decades. Hot research topics and future directions in this field have also been discussed. By applying the inclusion and exclusion criteria, a total of 250 documents were finally retrieved for analysis. Through production, citation, and content analysis with the help of Biblioshiny, this study finds that language teachers' self-efficacy research has increasingly gained popularity in the academic field over the past 20 years, and its booming production involves many authors, journals, institutions, and countries. Furthermore, English teachers' "professional development," "beliefs," "job satisfaction/burnout," and context impacting the construction of teachers' self-efficacy are the hotspots in language teachers' self-efficacy research. However, specific issues concerning measures to develop language teachers' self-efficacy and their effect on practical language teaching and learning will keep good topics in future research.