This systematic review presents the oral manifestations of paediatric Crohn's disease. Our review of 28 papers published from 2000 to 2015 showed that the prevalence of oral manifestations was 10–80%. Specific symptoms included mucosal tags, swelling of the lips, cheeks and gingiva, and cobblestoning mucosa. Nonspecific symptoms included aphthous‐like ulcers, angular cheilitis, lip fissuring and gingivitis. Conclusion The oral manifestations of Crohn's disease might precede intestinal inflammation or coincide with it. Crohn's disease should be considered in children with multiple oral manifestations and paediatric dentists, and gastroenterologists should be involved in their coordinated evaluation and follow‐up.