English academic writing has often been characterized as being direct, accurate, and objective. One way of achieving objectivity is through the use of a communicative strategy called impersonalization. The present research examines linguistic devices that academic writers have at their disposal to avoid explicit reference, especially to themselves, and to detach themselves from the information they convey. It also addresses the question of whether this impersonalization strategy is expressed differently across different disciplines. For these purposes, a corpus of 45 primary empirical research articles from the fields of linguistics, medicine, and natural sciences were analyzed both qualitatively and quantitatively with the help of corpus linguistic method. The results of the research showed that impersonalization in English research articles could be expressed through the use of agentless passive constructions and impersonal constructions. The results indicate that English academic discourse is marked by the use of agentless passive constructions (199.17 tokens per 10.000 words) to express impersonalization, which was primarily used to serve as writer-oriented hedging functions. The study also revealed highly significant differences in the use of impersonalization in linguistics, medicine and natural sciences. This seems to suggest that impersonalization in English academic discourse is expressed differently in different fields of study.