<p>The increasing use of WhatsApp has raised concerns about potential dependency and its impact on psychological well-being and quality of life, particularly among vulnerable populations such as those with social anxiety. This study investigates the moderating role of WhatsApp dependence in the relationship between social anxiety, psychological well-being, and quality of life. A cross-sectional study was conducted involving a sample of 264 undergraduate students aged 18 to 24 who were WhatsApp users. The data analysis included Pearson r analysis to test the correlations between variables, as well as multiple linear hierarchical regression for moderator analysis. The result revealed that WhatsApp dependence significantly moderated the link between social anxiety and the environmental mastery aspect of psychological well-being (<i>B</i> = 0.43, <i>p</i> = .004, ∆R2 = 0.03), and the social relationship domain of quality of life (<i>B</i> = 0.26, <i>p</i> = .046, ∆R2 = 0.02). The results show that individuals with higher levels of social anxiety tend to experience lower levels of environmental mastery and social relationship quality. WhatsApp dependence significantly moderates these associations. Specifically, WhatsApp dependence correlates with lower impairments in environmental mastery and social relationship quality of individuals with social anxiety. As a pilot study, these findings could inform future research aimed at confirming the cognitive and behavioral mechanisms underlying social anxiety in individuals when interacting on social media. In turn, this research can provide a foundation for developing more effective strategies to address social anxiety.</p>