Mouth breathing syndrome is a major harmful oral condition in children that causes them to switch from exclusively nasal breathing to mouth breathing or mixed breathing. It frequently happens as a result of an obstruction of the upper airway, which forces all or part of the air to enter through the mouth. Serious morphological and quality-of-life alterations are brought on by it. There are a number of causes for mouth breathing, but allergic rhinitis may be the most widespread, affecting more children. The second reason for this breathing pattern is palatine tonsils and adenoids. This multifactorial condition jeopardizes the balance of stomatognathic functions such as chewing, swallowing, breathing, and phonation, as well as creating conditions that influence the individual's development. Uncontrolled mouth breathing can have an adverse impact on the dentofacial system's health as well as aberrant dental and maxillofacial development. Based on the cause of mouth breathing, mouth breathers may demonstrate various dental development patterns, malocclusions, and maxillofacial development consequences. Furthermore, breathing through the mouth might harm dental health and raise the risk of periodontal and caries disorders. Because mouth breathers have several problems, a thorough and interdisciplinary clinical assessment is required to identify this syndrome early and reduce its negative effects on dentofacial development. This review finds that a multidisciplinary approach to these issues needs to make significant progress.