BACKGROUND: The spread of the coronavirus has led to significant anxiety among university students, resulting in various mental health problems that could potentially impact their academic performance. METHOD: To examine the mediating role of emotional regulation and online social support in the relationships between COVID-19 psychological pressures, depression, and the fear of missing out (FoMO) among young adult university students, a cross-sectional research design was employed using an online survey. The sample consisted of 521 full-time university students from China, currently enrolled in undergraduate and postgraduate programs. RESULTS: Findings revealed that more than half (55.09%, n=287) of the university students experienced COVID-19 psychological pressures. These pressures directly contributed to increased levels of depression (β = 0.339, p < .001) and fear of missing out (β = 0.236, p < .001). Moreover, online social support and emotional regulation exhibited partial mediating effects on the association between COVID-19 psychological pressures, depression, and the fear of missing out. The results indicated that COVID-19 psychological pressures were linked to higher levels of depressive symptoms and a greater fear of missing out among university students. CONCLUSIONS: However, the provision of timely and adequate online social support, as well as the implementation of emotional regulation strategies, mitigated the negative effects of the pandemic on students' social and emotional well-being. Consequently, this led to reduced levels of depression and fear of missing out.