Signs and symptoms of contact allergic reactions affecting the oral mucosa may mimic other common oral disorders, making diagnosis difficult. Patients frequently seek multiple consultations and do not receive the correct diagnosis or effective management. As intraoral contact allergy may be more prevalent than previously believed, a review of this topic is warranted. This article emphasizes signs and symptoms that suggest intraoral contact allergy, and the authors discuss the allergens that most frequently affect the oral mucosa.