Effective time-management skills and interpersonal interactions with familiar friends for learning matters on Facebook are desired characteristics for adolescents attempting to improve their academic achievements. This study identifies the relationships between time-management skills and Facebook interpersonal skills with the academic achievement of adolescents, and further investigates the predictors of academic achievement. In total, 1052 valid questionnaires were obtained from Taiwanese junior high school students. Data were analyzed using Pearson correlation analysis and multiple regression analysis. Analytical results reveal that Facebook-based interpersonal skills are negatively correlated with academic achievement, implying that Facebook-based interpersonal skills for social rather than for academic purposes in daily life are deterrent forces for academic achievement. Additionally, this correlation between interpersonal skills and academic achievement was moderated by time-management skills. Above results demonstrate that adolescents who converse less with friends for social purposes on Facebook may contribute to their academic performance, owing to their effective time-management skills. Based on a comparison with the results of the literature, we conclude that use of Facebook can increase the quality of interpersonal interactions for learning among adolescents, ultimately improving their academic achievement.