In this research, the potential of Facebook groups used in an online course in order to establish social presence was examined. Qualitative research methodology was used in this study. The participants of the study were 12 senior undergraduate students taking the School Experience course online over a period of 12 weeks. A Facebook group where announcements and deep discussions were made and files were shared was used. Facebook group posts as document data; and student interviews as interview data were collected. According to the results, it was found that Facebook groups established social presence. Social presence involves three categories; affective expression, open communication and group cohesion. Paralanguage, emotion, humor and self-disclosure emerged as indicators in the affective expression category. Acknowledgement, agreement, invitation and continuing a thread were found as indicators in the open communication category. Greetings and salutations, vocatives, group reference, social sharing and collaboration were found as indicators in the group cohesion category. A similar study can be conducted by collecting quantitative data from a large number of participants using the social presence scale. Other social networks' potentials to establish social presence can be examined. Since Facebook groups establish social presence, they can be used to support online or face-to-face courses.