The studies on L2 argumentative writing have surveyed different dimensions of learners’ argumentative behavior and performance. However, less attention has been given to the strategies and techniques enhancing students’ argumentative repertoire. As such, the current study, taking a pedagogy-based perspective, examined the argumentative writing behavior of 30 Iranian IELTS candidates before and after the instruction in both English and Persian languages. The sample questions were of the previous IELTS Writing part 2 essays from a real test by Cambridge University Press, chosen by 3 IELTS instructors in the Institute to meet the research objectives. To this end, 180 IELTS Task 2 argumentative essays were analyzed by 30 volunteers, each having 6 essays, at least 250 words, (Persian and English). As for the students’ English and Persian argumentative writing performance, the results indicated that there were significant differences between the EFL learners’ overall means on English argumentative tests. Furthermore, the candidates chiefly applied ‘data’ and ‘claim’ most frequently in both languages with secondary elements of argument (i.e., counterargument claim, counterargument data, rebuttal claim, and rebuttal data) as the least produced elements detected in the essays. The results demonstrate that a sound pedagogy in argumentation can both influence the use of argumentation elements in both English and Persian written texts. The pedagogical implications for writing instruction and argumentative writing are discussed. Manuscript profile