The main purpose of this study was to examine students’ roles and behaviors that take place under these roles in online learning environments. The research group consisted of 11 graduate students in a blended course (i.e., they received face to face instruction in the classroom and used web-based materials). Three hundred and ninety-one messages posted by students were analyzed. According to results, in an online learning environment, students act out two basic objectives: “developing group process and implementing group works”. Under two objectives, eight roles (supervisor, atmosphere constructor, reminder, information provider, instructor, opinion provider, trouble-maker, problem solver) and fifteen behaviors related to these roles has emerged. Of eight identified roles, the most common were opinion provider and atmosphere constructor. In addition, both in terms of participation status and collaboration behaviors, students were more active in the discussions that started by them.