Thomas Diafoirus is a doctor from the play Le Malade imaginaire by Molière. He is portrayed as a pedantic man who loves to use elaborate scientific terminology but is not overly concerned with his patients' actual health. The character of Thomas Diafoirus and his father "monsieur Diafoirus", also a doctor in the play, are closely related to the "Dottore" character in the Italian Commedia dell'arte.