Abstract  The present work is a quantitative and qualitative analysis of pragmatic strategies for delivering critique, and types of politeness, used by undergraduate L2 students of English at different stages of peer-review discussion. The material examined consists of four corpora of authentic conversations between students, the main purpose of which was to give feedback on each other’s contributions during an English A-level course, at Mid-Sweden University. The conversations explored were carried out electronically, and represent four different online environments, or modes of computer-mediated communication (CMC). The material from the two asynchronous modes of CMC is comprised of L2 students’ written discussion board messages and spoken posts recorded using online software. The two synchronous environments under investigation are text-based and voice-based chat. Taking Brown and Levinson’s (1987) framework of politeness as a point of departure, the present study uses a combination of corpus and conversation analytical methods. The basic unit of analysis has been defined as the shortest message of peer-review critique that constitutes a thematic unit: these have been examined in terms of their content and politeness features associated with them, and analyzed in terms of the pragmatic strategy and type of politeness adopted. The types of pragmatic strategies or message organization patterns at different stages, i.e. initial versus subsequent feedback, of the peer-review discussion have also been analyzed. The results of the study show that the pragmatic strategies aimed at praise and agreement prevail in the corpus data produced by predominantly native speakers of Swedish. Even though the pragmatic strategies used for disagreement and negative evaluation are rich in propositional content, their occurrences and distribution vary across the four modes of CMC examined. These results seem to have wider implications in the context of online L2 learning activities, providing insights about the language of peer-review critique in a Swedish academic setting.   Keywords: computer-mediated communication (CMC), Conversation Analysis (CA), conversation management, discussion boards, feedback category, mode of CMC, peer-review discussion, politeness theory, pragmatic strategy, speech act of critique, text-based chat, type of politeness, voice-based chat, VoiceThread