This study investigates factors contributing to student engagement in an educational Facebook group. The study is based on survey results of 138 undergraduate mathematics students at a highly diverse urban public university. Survey measures included engagement in the Facebook group, access to Facebook, comfort using technology, and interest in the class. Quantitative analysis found that interest in the class and access to technology both positively correlate to engagement in a Facebook group. The results suggest that integrating a familiar technology in a novel way requires instructor effort, knowledge, and technique. Study findings are discussed in terms of the TPACK framework (technological pedagogical content knowledge), developed by Mishra & Koehler (2006), emphasizing the importance of instructor preparation for effective instructional technology integration.