Taddeo da Suessa (or da Sessa) (c. 1190/1200 – February 18, 1248) was an Italian jurist. Born in Sessa Aurunca (modern Campania), he was introduced to Emperor Frederick II's court by Pier delle Vigne. Appointed as gran giustiziere (Great Justicier) of the Kingdom of Sicily, he became one of the main advisers to the emperor. Taddeo and Pier were ambassadors to Pope Gregory IX and, after 1244, to Innocent IV. In 1245 Taddeo unsuccessfully defended the cause of the excommunicated emperor at the Council of Lyon against the unjustified accusations made against him by Innocent.