Vitamin D deficiency is common in patients with inflammatory bowel diseases and may even precede the disease onset contributing to an increased risk. Using comprehensive data from a large, referral IBD cohort, Kabbani et al. establish that low vitamin D levels are associated with greater disease activity, increased risk of surgery and hospitalizations, and lower health-related quality of life in patients with IBD. This expands the evidence base supporting such an association. However, there is a need for this field to evolve to interventional studies with vitamin D supplementation to confirm that vitamin D has a true therapeutic role for treating disease activity in IBD.