Leo of Synada (ca. 940 – after 998) was a Byzantine cleric, diplomat and writer of the late 10th century. Born ca. 940, Leo served as synkellos before becoming metropolitan bishop of Synada in Phrygia. In 996–998, he was sent as an envoy to the Pope in Rome along with a certain Kalokyros. During this embassy, Leo supported the antipope John Philagathos, despite his strong personal dislike of the man. Leo was also involved in a mission to the court of "Frankia" (the Holy Roman Empire under Otto III) to negotiate a marriage alliance with Constantinople.