The present study examines a corpus of ninety discussion sections of applied linguistics research articles, with the goal of analyzing different aspects of academic written discourse. Three types of texts were considered: English texts written by native speakers of English, English texts written by Iranians (as non-natives of English), and Persian texts written by Iranians. In order to understand the cultural differences between Persian and English-speaking researchers, the following metadiscourse sub-types adapted from Hyland's (2004) model were examined: transitions, frame markers, endophoric markers, evidentials, code glosses, hedges, boosters, attitude markers, engagement markers, and self-mentions. The first five comprise interactive metadiscourse, and the rest comprise interactional metadiscourse. After the detailed analysis of the metadiscourse types in question, chi-square tests were carried out to clarify the probable differences. The analysis revealed how academic writings of these groups differed in their rhetorical strategies using metadiscourse type because of their respective mother tongues. However, the different groups were found to use all sub-types of metadiscourse. Yet, some subcategories were used differently by the writers of these two languages. In addition, interactive metadiscoursal factors (those resources which help to guide the reader through the text such as transitions, frame markers, etc.) were used significantly more than interactional metadiscoursal factors (those resources involve the reader in the argument such as hedges, boosters, etc.) by both groups.