Studies have examined the relationship between Facebook use and student engagement. With the growing use of social networking services in everyday life, there is an ongoing debate on the effect of Facebook usage outside the classroom on classroom learning. However, studies have been so far failed to examine how Facebook activities in everyday life differ according to individual characteristics. In order to answer that question, this study investigated how Facebook use affects student engagement in the classroom. The moderating role of user motivation was also examined, since students use Facebook for different purposes, which eventually determine whether they become engaged in their learning. The results revealed that students with more active Facebook use achieved significantly higher scores on student engagement than those with less active Facebook use. Image-management and social-pressure motivations have moderating effects on the relationship between the differing ways of using Facebook and student engagement. Students with high levels of image-management motivation who spent more time on Facebook gave learning with peers the lowest ratings of all the students surveyed. Those with high levels of social-pressure motivation who spent more time on Facebook also gave learning with peers lower ratings than all other students surveyed. Implications for future studies on instructional uses of social networking services are suggested.