This study aimed to investigate the underlying mechanisms through which social media (SNS) addiction influences college students' academic performance. We developed an integrated model of the relationship between SNS addiction and academic performance based on the dual-systems theory. A total of 251 college students participated in this study. Partial least squares structural equation modeling (PLS-SEM) was used to analyze the empirical data. The results indicated that self-control mediated the impact of social media addiction on college students' grade point average (GPA). Moreover, social media addiction had a positive impact on their anxiety and stress, which in turn negatively moderated the positive relationship between self-control and GPA. Educators can use these findings to improve the academic performance of college students with SNS addiction.