Introduction <p>The role of vitamin D supplementation in modulating clinical outcomes and inflammatory responses in COVID- 19 patients has garnered significant interest. This umbrella review consolidates current evidence to evaluate the association between vitamin D supplementation and COVID- 19-related outcomes.</p> Methods <p>A comprehensive search was conducted across multiple databases to identify relevant systematic reviews and meta-analyses. Studies assessing the impact of vitamin D supplementation on disease severity, mortality, hospitalization, and inflammatory markers in COVID- 19 patients were included. Methodological quality was assessed using standardized tools.</p> Results <p>The findings suggest that vitamin D supplementation may be associated with reduced mortality and improved clinical outcomes in COVID- 19 patients. Several studies reported a decrease in inflammatory markers, such as C-reactive protein and interleukin- 6, following supplementation. However, variations in study design, dosage regimens, and baseline vitamin D status limit the generalizability of results.</p> Conclusion <p>Vitamin D supplementation appears to have a potential role in improving clinical outcomes and modulating inflammatory responses in COVID- 19 patients. Nevertheless, due to heterogeneity among studies, further high-quality randomized controlled trials are warranted to confirm these findings.</p>