On the one hand, the success of English for Academic Purposes (EAP) courses has long been a goal for English language teaching practitioners. On the other hand, one of the major concerns of EAP specialists is the way EAP is influenced by the students' General English Proficiency (GEP) levels. The current study thus aimed at investigating the relationship between General English Proficiency and L2 achievement of Iranian students. To this end, 81 Iranian EAP students of Humanities (i.e. Arabic Language and Literature, Persian Language and Literature, Education and Theology) at Bu-Ali Sina University participated in the study. The participants had already passed a pre-requisite General English course prior to the EAP course. The participants, General English Course scores and their EAP (i.e. specialized English) final exam Scores were collected from the university and were then correlated. The results of person correlation between the General English scores and EAP scores of the participants indicated that there was a significant positive relationship between the two variables. Additionally, the content analysis of a semi- structured interview conducted whit 20 participants selected randomly from among the participants of the study, revealed almost all of them highlighted the significant role GEP played in the ultimate success of the EAP students. The findings imply that the GEP of EAP students be seriously worked on and enhanced before they enter EAP courses; and issue of paramount importance which is typically undervalued and ignored in EAP education in Iran.
