The main objective of this study was to examine the moderating or buffering effect of social support (SS) perceived by university students on the psychological impact of lockdown on mental health. Specifically, a total of 826 participants (622 women) completed an online survey that included standardized measures of anxiety (Generalised Anxiety Disorder‐7), depression (Patient Health Questionnaire‐9), and irritability (Brief Irritability Test), as well as measures of stressors, perceived SS, and self‐perceived change in mental health. The results of hierarchical regression analyses suggest that SS contributes toward attenuating the negative impact of academic stressors, general overload, and interpersonal conflict on the indicators of psychological well‐being; however, moderation analysis only confirms the buffering effect for symptoms of anxiety. In conclusion, it is suggested that SS networks need to be strengthened as a basic means of protecting health and well‐being during unexpected disasters.