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Abstract The COVID‐19 pandemic has emerged as a major global health crisis. Vitamin D, a crucial fat‐soluble vitamin, has been recommended for COVID‐19 patients, though evidence of its effectiveness is inconsistent. This systematic literature review and meta‐analysis aimed to evaluate the impact of vitamin D supplementation on COVID‐19‐related outcomes. A comprehensive search was conducted across PubMed, Scopus, Web of Science, Embase, and Cochrane databases. Primary outcomes included mortality and hospital length of stay, while secondary outcomes encompassed C‐reactive protein (CRP), ferritin, D‐dimer, hemoglobin (Hb) concentrations, and lymphocyte, neutrophil, and platelet counts. Data analysis was performed using Stata™ Version 14. A total of 16 trials were analyzed. The meta‐analysis revealed that vitamin D supplementation significantly reduced hospital length of stay (mean difference = −1.16; 95% confidence interval [CI]: −2.23, −0.09; p = .033) with significant heterogeneity (I2 = 69.2%, p = .002). Subgroup analysis showed a more pronounced reduction in studies with vitamin D dosages ≤10 000 international units (IU) (mean difference = −1.27; 95% CI: −1.96, −0.57; p < .001) and in patients over 60 years old (mean difference = −1.84; 95% CI: −2.53, −1.14; p < .001). Additionally, vitamin D significantly reduced CRP concentrations in older adults (>60 years) (mean difference = −1.13; 95% CI: −2.07, −0.18; p = .019). No significant changes were found in ferritin, D‐dimer, Hb concentrations, or in lymphocyte, neutrophil, and platelet counts (p > .05). In conclusion, while vitamin D supplementation did not significantly affect most COVID‐19‐related biomarkers, however, it reduces the length of hospital stay.