Social networking sites (SNSs) such as Facebook have a potential to become a valuable learning environment. Facebook games with appropriate instructional design may provide players with better learning experiences and outcomes. Using an effective educational Facebook game, we aimed to explore the educational effects of Facebook games as self-directed e-learning environments. We tested our hypotheses on a sample of 73 undergraduates (42 females). The participants completed the Facebook game and self-administered questionnaires over a 3-week period. Path analysis demonstrated that Internet self-efficacy, usability, and fun positively affected perceived learning effectiveness and user satisfaction in a Facebook learning environment. We discussed the research and practical implications of these findings for the future development of self-directed e-learning on SNS.