The current study was aimed at investigating the relationship between academic Iranian EFL learners' extroversion/introversion and their writing performance. The participants of the study were some 52 BA learners majoring in English language literature in Urmia and Tabriz state universities. The chosen sample comprised of both males and females and as convenience sampling was utilized, all the participants took part in the study on a voluntary basis. The major instrument used in the study was the online version of Eysenck's personality questionnaire, which was exerted as the means of determining the learners' extroversion/introversion. Furthermore, to gauge the learners' writing performance, they were asked to write three types of essays (argumentative, narrative and descriptive). Through the final analysis of data, it was revealed that no significant correlation held between the participants' personality types and their writing performance in terms of all three modes referred to. A statistically significant difference was, however, observed between the writing performance of male and female students.