Introduction: On a global level, the prevalence of respiratory tract infections (RTIs) is more than any other type of infection in children. One of the possible causes of the development of these infections is the deficiency of Vitamin D. In the process of synthesis of peptide cathelicidin, a vital role is played by Vitamin D. Peptide cathelicidin eventually protects against the microbial activity of certain infectious bacteria and viruses. It also causes the prevention of replication of the influenza virus. Moreover, Vitamin D also increases the immunity of the body. The presence of a normal physiological level of Vitamin D in the body is highly advantageous in the protection of the body against RTIs. Aim/Objectives: To assess the correlation of Acute Respiratory Tract Infection with Vitamin D deficiency in children. Methodology: A total of 120 children were included in the study. The age range of the participants was from 1 months to 5 years. A questionnaire was prepared to record the medical histories of all the patients. For the identification of the level of Vitamin D, blood samples of all the participants were collected and sent to the laboratory of the hospital. According to the exclusion criteria, the participants having genetic diseases such as hypophosphatemic rickets, X-linked rickets and hereditary vitamin D-resistant rickets, were excluded from the study. Results: The average level of vitamin D in the participants with normal vitamin D was 15__ampersandsignplusmn;9.5 ng/mL. Whereas, the average vitamin D level in participants having respiratory tract infection was 5__ampersandsignplusmn;5.2 ng/mL/ which was much lower compared to the healthy individuals. The level of vitamin D had shown association with lower, upper and recurrent infections of the respiratory system (p __ampersandsignlt;0.05). The common symptoms of such infections observed in the present study were pneumonia in the upper respiratory tract, lower respiratory tract, common cold, and recurrent infections in the respiratory tract. The gender and age of the participants had no significance over the results. Conclusion: Vitamin D has a significant association with respiratory tract infections in children.