Owing to the features associated with English for Specific Purposes (ESP), ESP teachers are expected to play different and additional roles. The purpose of the study is to examine and investigate the roles Iranian ESP teachers believe they should play and the roles they play in practice. Dudley-Evans and St. John (1998)’s five-component model for ESP teachers’ roles worldwide was used as the analytical framework. Twelve subject teachers and two language specialists offering ESP took part in the study. To collect data, semi-structured interviews and live classroom observations were employed. Interpretive analysis of data suggested that Iranian ESP instructors, particularly content teachers, fall short of the roles espoused in the model; language specialists’ perceptions and practices are more compatible with the features associated with the roles in the model. Drawing upon interview and classroom observation data, the dominant roles Iranian ESP teachers play are discussed followed by a discussion of some potential causes. In the final section, suggestions pertaining to de-jure and de-facto ESP planning and practice are made.
