Ho, Pui InPui InHo2025-12-152025-12-152025-11https://dspace.usj.edu.mo/handle/123456789/6748Introduction: This study examines the impact of social media use (SMU) on self-esteem and emotional problems among Macao adolescents, using Social Comparison Theory (Festinger, 1954). It aims to investigate self-esteem (using the Chinese Rosenberg Self-Esteem Scale) as a mediator and gender as a moderator in the relationship between SMU (measured by daily time use of five social media platforms, and the Motivations for Social Media Use Scale), and emotional problems (assessed by the Strengths and Difficulties Questionnaire - Emotional Symptoms subscale). A moderated mediation model (Model 1) and a mediation model (Model 2) are proposed. Method: A cross-sectional study involved 267 secondary students (aged 12–18) from two Macao private schools, using self-report questionnaires. Hayes' PROCESS macro (Models 59 and 4, with 5,000 bootstrap samples) analyzed moderated mediation for time-use and mediation for motivations. Findings: In Model 1, no significant mediation by self-esteem or moderation by gender in the link between daily SMU time and emotional symptoms, rejecting all related hypotheses and suggesting time-based measurement alone fails to predict outcomes. In Model 2, self-esteem partially mediated the relationship between MSMU Connection and emotional symptoms (indirect effect = 0.09, 95% CI [0.03, 0.15]), with direct effects significant for Popularity, Appearance, and Values/Interests subscales, but no mediation. Results indicate that Connection-driven SMU may trigger upward social comparisons, reducing self-esteem and increasing emotional distress, particularly in Macao’s collectivist context. Implications: To buffer against the negative impacts of SMU, recommend implementation of school-based social media literacy and mindfulness practices to enhance self-esteem and emotional regulation. This study’s significance lies in its in-depth exploration of SMU among Macao adolescents, integrating time and motivational dimensions, to provide an understanding of the underlying psychological mechanisms and to propose practical mental health interventions.enSocial media useSelf-esteemEmotional problemsAdolescentstext::thesis::master thesis