<p>With the development of mobile Internet technology, social media use is becoming a global issue, followed by the phenomenon that social exclusion on social media (cyberostracism) is increasingly serious. This study adopts a cross-sectional approach to clarify the relationship between cyberostracism and adolescents’ life satisfaction, and construct a moderated mediation model, focusing on the mediating role of self-esteem and the moderating role of rumination. A survey was conducted on 693 adolescents (M_age = 15.91 years; 56.85% boys) from February to April 2022 using the Cyberostracism Scale, Students’ Life Satisfaction Scale (SLSS), Rosenberg Self-Esteem Scale, and Ruminant Response Scale. A path analysis was conducted using Hayes’ PROCESS macro in SPSS 26.0. The results indicated that cyberostracism was significantly and negatively associated with life satisfaction after controlling for gender and age. Self-esteem mediated the relationship between cyberostracism and life satisfaction, and the indirect effect was moderated by rumination. Compared with individuals with low rumination levels, the indirect association was stronger in those with high rumination levels. These results indicated that cyberostracism can indirectly affect life satisfaction through self-esteem, and rumination plays a moderated role in it. These findings can help maintaining and promoting adolescents’ physical and mental health on the mobile Internet and provide useful suggestions for education and administrative departments. In the future, longitudinal tracking studies can be used to explore the deep relationship between cyberostracism and life satisfaction.</p>