Although social networking sites (SNS) have been widely investigated, very limited information is available about how teachers navigate them within a fully online learning space, the challenges they confront, and the strategies they use to overcome them. Thus, we examined these underexplored areas by interviewing 14 higher education teachers in the field of social sciences. Using a cross-case analysis, overall data indicates that teachers had varied reasons for and considered different factors when adopting SNS for online teaching. Our study also reveals that they used SNS affordances depending on their own teaching contexts and took different roles when teaching online via this platform. Although teachers generally viewed SNS as an instructional approach, they also reported several technical, pedagogical, and learner-related challenges, which they attempted to confront using a variety of strategies. These findings confirmed that teachers’ pedagogical practices and decisions in an SNS-mediated learning environment are shaped by the interaction between and among the teacher-related factors, SNS as an instructional tool, and teaching goals mediated by the policies (existing or not) and their peers. Some key implications of our findings are on designing teacher development programs, recalibrating national, institutional, and classroom policies, and implementing a systemic approach to mitigating pedagogical challenges in an online learning space. Implications for future studies are also discussed.