Celiac disease (CD) is a chronic, small-intestinal, immune-mediated enteropathy due to gluten exposition in genetically predisposed individuals. It occurs in about 1% of the population and often remains an underdiagnosed condition. This could be due to the fact that the adult population often lacks the classical signs and symptoms of CD, manifesting only atypical symptoms. In this review we analyzed the main extra-intestinal manifestations of CD which include cutaneous and endocrinological disorders, abnormal liver function tests, and neuropsychiatric features. When CD is not diagnosed and therefore is not treated with a gluten-free diet (GFD), it can predispose to severe complications, not only gastrointestinal. Thus, it is important for clinicians to quickly recognize the atypical manifestations of CD, considering that an early diagnosis can significantly impact on a patient’s prognosis.