This cross-sectional study examines the prevalence of vitamin D deficiency among a diverse population in Western Uttar Pradesh, India. Blood samples from participants across various age groups, genders, and socioeconomic backgrounds were analyzed to measure serum 25-hydroxyvitamin D levels, while data on dietary habits, sun exposure, and lifestyle factors were collected through structured questionnaires. The findings indicate a high prevalence of vitamin D deficiency, levels falling below the recommended levels, particularly among women, elderly, and urban residents. Contributing factors include limited sun exposure due to cultural practices, indoor occupations, and inadequate dietary intake. This study underscores the need for public health interventions, such as increasing awareness about the importance of sunlight exposure, dietary improvements, and possible supplementation, particularly for at-risk groups. Further research is needed to understand the long-term health consequences of vitamin D deficiency in this region.