Grisel syndrome or atlantoaxial non-traumatic subluxation is a rare entity, poorly described in pediatric literature, although it is a pathology that usually appears in young children. The typical presentation is a torticollis with a previous surgical antecedent (mainly a surgery of the ear, nose, and throat area like adenoidectomy) or after an upper tract respiratory infection. A prompt diagnosis is essential for a successful evolution, and the treatment in most cases is conservative. We report a case of an 8-year-old girl with a typical evolution of this unusual complication. In our case, the most important element for diagnosis was the 3D CT scanner, and the treatment was conservative with a successful outcome. Pediatricians should be aware of this rare but potentially serious entity to establish the correct treatment and avoid complications.