Background: Vitamin D, in various forms, is recognized for its significance across multiple stages of carcinogenesis. It exhibits anti-oxidative stress, anti-invasion, anti-angiogenesis, and anti-proliferative effects. Vitamin D deficiency is common in cancer patients and is associated with disease progression. Palliative cancer patients often experience vitamin D deficiency, linked to an elevated risk of pain, infections, and depression, impacting their Quality of Life (QoL). Materials and Methods: A cross-sectional study was conducted, involving n=48 cases of advanced gallbladder cancer undergoing palliative chemotherapy (gemcitabine and cisplatin) in the Department of Surgery, King George Medical University India. All enrolled patients received oral supplementation of 60,000 IU of vitamin D and 1000 mg of calcium. Quality of life was assessed using the FACT-G questionnaire before initiating chemotherapy and after completing 6 cycles. Results: The observed median survival was 35.7 weeks (approximately 9 months). Post-chemotherapy, there were no significant changes in serum vitamin D and calcium levels or functional aspects. However, there were significant improvements in physical, social and emotional dimensions. The overall quality-of-life score exhibited significant changes with a p-value of 0.021. Conclusion: The study indicates that vitamin D and calcium supplementation do not significantly alter serum values in patients undergoing palliative chemotherapy for advanced gallbladder carcinoma. However, in the context of Quality of Life, supplementation with Vitamin D and Calcium has notable positive effects on physical, emotional, and social aspects, as well as total quality of life scores.