Researchers in education have documented that teachersâ€™ sense of efficacy has strong impacts on various aspects of teaching and learning. Yet, in the field of TESOL, inquiry into teachersâ€™ sense of efficacy is extremely scarce. The present study, by adopting the notion of teachersâ€™ sense of efficacy as the theoretical framework, has explored Iranian English Institute teachersâ€™ confidence in teaching English. The study has also examined teachersâ€™ attitudes toward the English language and teachersâ€™ English language proficiency, respectively. An exploratory survey methods design was employed in the present study and data were collected in the quantitative format, by which 68 English institute teachers working in Mazandaran responded to the survey. The results indicated that teachersâ€™ current level of English proficiency and EIL (English as an International Language) attitude toward the English language were the significant predictors for teachersâ€™ English teaching-specific efficacy beliefs or confidence. Also, efficacy for oral English language use was found as an additional dimension of teacher efficacy in teaching English, indicating that in a foreign language context, oral target language use would be a significant dimension to be considered in examining teachersâ€™ self-efficacy in teaching the target language.