Jean Riolan (the Younger) (15 February 1577 or 1580 – 19 February 1657) was a French anatomist who was an influential member of the Medical Faculty of Paris. His father, Jean Riolan (the Elder) (1539–1605) was also a noted French anatomist. Riolan was the personal physician to Marie de' Medici (1553–1642) for all his life. Riolan attacked Thomas Bartholin on the question of the latter's discovery of the lymphatic system.