Despite English teachers' acknowledgement of the plurality of English and the emergence of different varieties of the language, the actual manifestations of this plurality and the associated principles do not seem to be equally embraced in their classroom approach. Against this background, this study investigated Iranian English teachers' conceptions of English as an International Language (EIL) and their corresponding instructional practices through semistructured interviews and non-participant classroom observations. Drawing upon the theory of planned behavior (TPB), as the theoretical/analytical framework, the researchers explored the participant teachers' behavioral, normative, and control beliefs underlying their intentions and actual classroom practices with regard to EIL. Findings revealed that although the teachers acknowledged the importance of raising learners' awareness of EIL in different aspects of their language use, they still leaned towards standard American or British English in their actual instructional practices. Such propensity was informed by their attitudes toward the inclusion of EIL principles, their perceptions of the existing social pressures, and their perceived difficulty of adopting an EIL-aware pedagogy. Moreover, the participant teachers' actual classroom instructions were found to be incongruent with their beliefs about the importance of raising students' awareness regarding different English varieties. Implications for language teacher education are discussed.