This study investigated metadiscourse and its subcategories in English research articles (RAs) written by nonnative (Iranian) and native English writers from the two disciplines of applied linguistics and civil engineering. The study aimed at seeing whether language and discipline influenced the frequency of occurrence of metadiscourse elements in research articles. To this end, a sample of 120 research articles was analyzed in terms of the use of metadiscourse and its subcategories based on the model proposed by Hyland & Tse (2004). The AntConc text concordance software program was used to search for the metadiscourse elements in the corpora. The results of the data analysis showed that the writers from the two disciplines were significantly different in using metadiscourse elements collectively; however, no difference was found due to language background of the writers. With regard to different subcategories of metadiscourse, the results revealed that the four groups of writers from the two disciplines and the two languages used different types of metadiscourse differently.