Social presence in a virtual learning environment: an analysis proposal in light of Systemic Functional Linguistics is an interpretive case study of the elements which contribute to co-presence (Goffman, 1963) and to the presentation of the self (Goffman, 1959/2009) in an online pedagogical context. Adopting a Systemic Functional view of language (Halliday, 1994) and drawing on the study of the variables Field, Tenor and Mode (Halliday and Hasan, 1989) and Appraisal Theory (Martin, 2000), this thesis examines 510 texts written by thirteen language teachers in a ten-week-course held in TelEduc, whose aim was to enable participants to produce digital teaching materials. The corpus contains samples that are representative of the linguistic exchanges in the students’ profiles, forum messages and portfolio messages. The theoretical and methodological framework of the study encompasses the discursive functions which make writing more interactive, specifically, the resources that simulate speech in the written mode and the students’ lexicogramatical choices as regards Participants and Processes as well as expressions of Affect, Judgment and Appreciation. The study also categorizes the types of messages posted and analyzes how they relate to one another to form conversations (chains) between participants. The study shows that the profile is the only tool in which there is a single social action. In the eleven forums and in the 13 portfolios, where six other actions take place, requests and offers for help or moral support are the most frequent, followed by feedback on the activities designed by colleagues. This suggests that the practical nature of the course makes the reflections on the readings and model activities less frequent, despite being compulsory. There are also messages whose objective is just socialization (apologies for example), selfassessment, and description of the activities posted on the portfolios. Depending on the Field and the tool, these actions are most commonly performed independently, generating single communicative purpose texts (Simple Field samples) or they may be combined, for example, an apology, a reflection and evaluation in one text (a Combined Field sample). Authors use this kind of combination mainly so that they can save face. The discourse function identifying with peers and the resources used for simulating speech, which make writing more personal and interactive, greatly contribute to build a sense of community. The participants’ perceptions, collected in two online questionnaires and in an email interview, provide further information that complements the linguistic study of the participants’ realization of social action. The triangulation of the linguistic behavior observed and the participants’ opinions shows that there are some mismatches between what can be expected from the survey of the literature and what happens in the online space of interaction. In particular, the triangulation highlights the expectation of answers in the forums, detected through the analysis of the discursive functions asking question and questioning, and the content of the profiles. Such evidence points to possible pedagogical implications, which could involve a review of practices in online courses.