This research is a qualitative case study of the EFL curriculum in an Iranian high school. My aim has been to understand and interpret that curriculum, and in this way, to explore some of the likely reasons for the pupils' underachievement in their communicative ability. This target is approached through the implementation of ethnographic techniques of class observation, interview, and document analysis. To delineate the areas of the research and to take account of the research context of situation, I have devised and applied an EFL curriculum evaluation frame appropriate for the study of EFL curriculum in the Iranian high school. Through this study, I have made certain 'analytical inductions' about the EFL curriculum in that high school. I have argued that we seem to need a lens, different from that of the quantitative experimental approach, so as to enable us to explore and look at the issues concerning EFL curriculum and underachievement more widely and clearly. I have also discussed that merely borrowing the concept of communicative competence is not enough to improve the pupils' ability to communicate. Certain principles and prerequisites need to be met to enhance this ability. For instance, social construction of knowledge, collaboration of the pupils on the teaching and learning processes, and their involvement in language activities can contribute to the enhancement of the pupils' communicative competence. I have also hypothesised that loosening institutional constraints and making teachers conscious of the distinction between broader and narrower concepts of communicative competence might help to operationalise broader concepts of communicative competence in the high school EFL classes. The above arguments are made through evaluation research of the EFL curriculum in a high school by demonstrating that there is rather loose congruence between the curriculum components and that relatively recent approaches to learning and teaching are not reflected appropriately in that curriculum.