Grisel's syndrome is a non-traumatic subluxation of the atlantoaxial joints, which is caused by an inflammatory process involving the upper neck. Torticollis, neck pain, and reduced neck mobility are the main clinical signs of presentation. Predisposing factors are trauma, hyperlaxity of the transverse and alar ligaments of the atlantoaxial joints, and surgical interventions carried out in this area. Several viral and bacterial pathogens have been reported as causative events of Grisel's syndrome, including Epstein-Barr virus, Kawasaki disease, Streptococcus pyogenes, Staphylococcus aureus, and other infectious agents. Grisel's syndrome linked to Mycoplasma pneumoniae infection as the trigger has not previously been reported. Mycoplasma pneumoniae is a small prokaryotic microbe and a frequent etiologic factor of respiratory tract infections and, less frequently, of extrapulmonary body organs. The recognition of the Grisel's syndrome is based on clinical and neuroradiological investigations, and early diagnosis and specific treatment are crucial to the successful outcome of the disease.