Abstract Background and objectives: Maneuvers precluding the downward shift of the mandibula and providing slight extension of the head have been shown to increase upper airway dimensions. This study aimed to investigate the role of Neck Collars (NC) in maintaining airway patency during Magnetic Resonance Imaging (MRI) examination in a pediatric population aged between 0 and 16 years. Methods: One hundred twenty-five children were recruited in this prospective study. Subjects were randomly assigned to NC group (NC+) or standard imaging group (NC-). Measurements of anteroposterior and transverse dimensions and cross-sectional area were performed to determine the upper airway size at three distinct levels: soft palate, base of the tongue, and tip of the epiglottis. Results: The anteroposterior diameter and cross-sectional area at the levels of base of the tongue and soft palate were significantly higher in NC+ patients compared to NC- patients. However, anteroposterior dimensions and cross-sectional areas at the epiglottis level were similar in the two groups. When patients were analyzed according to age groups of 0-2, 2-8, and 8-16 years, the anteroposterior diameter and cross-sectional area at the levels of base of the tongue and soft palate were significantly higher in NC+ patients compared to NC- patients in all age groups. Conclusions: This study clearly demonstrates that the application of a NC may improve retropalatal end and retroglossal airway dimensions in a pediatric population undergoing MRI examination and receiving sedation in supine position.