Nocturnal bruxism in children refers to the behavior of children who fall asleep at night due to strong, sustained, nonfunctional contractions of the masticatory muscles, which cause grinding between the upper and lower teeth, resulting in a high-pitched, audible sound. It usually occurs during periods of rapid eye movement sleep. There is often a familial tendency. Its onset may be related to psychological stress, anxiety, or tension. Organic factors associated with teeth grinding include middle ear effusion, allergic rhinitis, anal itching or pinworm infections, chronic abdominal disorders and neurologic disorders such as meningitis or cerebral palsy, as well as oral disorders such as missing, overgrown, poorly restored, and incomplete eruption of milk or permanent teeth. Teeth grinding can cause tension in the chewing muscles, temporomandibular joint pain, tension headaches, pain in the face and stiffness in the neck. Prolonged teeth grinding can cause permanent damage to the teeth and supporting tissues and chewing muscle pain. For teeth grinding caused by organic pathology the main focus should be on treating the primary pathology. For those without obvious organic lesions, the cause of the disturbing child’s emotions should be carefully identified and timely relief should be given so that the teeth grinding behavior stops on its own.