Background and Clinical Significance: Turner syndrome is associated with an increased prevalence of autoimmune disorders, particularly celiac disease, and is also associated with impaired bone health. The coexistence of Turner syndrome, celiac disease, and ulcerative colitis is rare and represents a challenging clinical scenario requiring multidisciplinary management; Case Presentation: We report the case of a 7-year-old girl referred for short stature who was diagnosed with celiac disease based on positive serology and duodenal histology (Marsh 3a/3c). Cytogenetic analysis revealed 46,X,i(X)(q10) Turner syndrome. Despite strict adherence to a gluten-free diet, persistent growth impairment led to initiation of recombinant human growth hormone therapy. At 14 years of age, she developed bloody diarrhea, weight loss, iron-deficiency anemia, and elevated inflammatory markers. Colonoscopy and histology confirmed extensive ulcerative colitis. During follow-up, dual-energy X-ray absorptiometry demonstrated reduced bone mineral density (lumbar spine Z-score −2.7; whole-body Z-score −2.5). At 16 years of age, treatment with azathioprine and 5-aminosalicylic acid was complicated by pancreatitis, with recurrence of pancreatic enzyme elevation following sequential drug reintroduction, leading to discontinuation of both agents. Infliximab therapy was subsequently initiated, resulting in sustained clinical, endoscopic, and near-complete histological remission. The patient was later transitioned to adult multidisciplinary care; Conclusions: The coexistence of Turner syndrome, celiac disease, ulcerative colitis, and low bone mineral density is an exceptionally rare combination of genetic susceptibility, autoimmunity, and chronic inflammation. This case highlights the importance of lifelong multidisciplinary surveillance in patients with Turner syndrome, including monitoring for additional autoimmune disorders, growth impairment, and skeletal complications.