Abstract Background There is currently a deficit of knowledge about how to define, quantify, and measure different aspects of daily routine disruptions amid large-scale disasters like COVID-19, and which psychiatric symptoms were more related to the disruptions. This study aims to conduct a systematic review and meta-analysis on the probable positive associations between daily routine disruptions and mental disorders amid the COVID-19 pandemic and factors that moderated the associations. Methods PsycINFO, Web of Science, PubMed, and MEDLINE were systematically searched up to April 2023 (PROSPERO: CRD42023356846). Independent variables included regularity, change in frequency, and change in capability of different daily routines (i.e., physical activity, diet, sleep, social activities, leisure activities, work and studies, home activities, smoking, alcohol, combined multiple routines, unspecified generic routines). Dependent variables included symptoms and/or diagnoses of mental disorders (i.e., depression, anxiety, post-traumatic stress disorder, and general psychological distress). Results Fifty-three eligible studies (51 independent samples, 910,503 respondents) were conducted in five continents. Daily routine disruptions were positively associated with depressive symptoms (r = 0.13, 95% CI = [0.06; 0.20], p < 0.001), anxiety symptoms (r = 0.12, 95% CI = [0.06; 0.17], p < 0.001), and general psychological distress (r = 0.09, 95% CI = [0.02; 0.16], p = 0.02). The routine-symptom associations were significant for physical activity, eating, sleep, and smoking (i.e., type), routines that were defined and assessed on regularity and change in capability (i.e., definition and assessment), and routines that were not internet-based. While the positive associations remained consistent across different sociodemographics, they were stronger in geo-temporal contexts with greater pandemic severity, lower governmental economic support, and when the routine-symptom link was examined prospectively. Conclusions This is one of the first meta-analytic evidence to show the positive association between daily routine disruptions and symptoms of mental disorders among large populations as COVID-19 dynamically unfolded across different geo-temporal contexts. Our findings highlight the priority of behavioral adjustment for enhancing population mental health in future large-scale disasters like COVID-19.