Self-efficacy is the belief in one‘s capabilities to organize and execute the courses of action required to manage prospective situations. The purpose of this study was to investigate the perceived and actualized self-efficacy of English teachers. Considering the importance of the topic, this study aimed to construct definition, item development, and validation of an ELT Teacher Perceived and Actualized Efficacy Asymmetry Scale. To this end, a questionnaire consisting of 4 main constructs, 21 sub-constructs, and 63 items was developed in 2 versions (teachers' perceived and actualized versions). The reliability and validity of both questionnaires were confirmed. SPSS and AMOS software were used to analyze the records and check the structural equation models. The results of SEM analysis for both questionnaires confirmed the existence of significant relationships. This research showed that these four constructs have an important effect on teachers' self-efficacy. By comparing the statistical results of the two questionnaires, it was found that teachers consider themselves to be more efficient than they actually are. In fact, they think that they have a great influence on the teaching and learning process, but in practice, their influence is less than they presume. The findings of this research will be very helpful to researchers in the field
