This study aimed to explore the function and frequency of textual metadiscourse markers (MDMs) in scientific English and Persian texts. Based on the qualitative and quantitative analysis of textual markers characterizing the selected genre, four different textbooks, two written in English and two in Persian were analyzed to identify the textual metadiscourse categories (including logical markers, code glosses, and sequencers) used in these texts and to determine the sociopragmatic differences existing in these languages, chi-square test was run and the findings suggested that textual MDMs were present in both English and Persian texts, but they differed in their frequency of occurrence. The contrastive comparison between the English and Persian texts revealed that the frequency of the textual MDMs was greater in the Persian texts. Therefore, it was concluded that such discrepancy could be attributed to the differing rate of explicitness in these two languages. The Persian writers were more interested in explicating their ideas for readers through the text via the use of textual markers (TMs) to a greater extent. It was further found that different factors may influence the use of MDMs, namely the culture, the writer's preferences, the text, and its genre. The implications could include the precaution that Iranian EFL writers ought to be advised to approximate their writing style, in terms of using MDMs, to that of native speakers of English while writing in English.
