Peanut allergy is one of the most serious of the immediate hypersensitivity reactions to foods in terms of persistence and severity of the reaction and appears to be a growing problem. Allergen-specific immunotherapy (IT) is currently being examined as a treatment option because of the persistence of this hypersensitivity reaction and the lack of effective treatment. An understanding of the molecular mechanisms of peanut-specific IT is vital to ensure the eventual, successful treatment of peanut-allergic patients.