This is a list of kings of Bithynia, an ancient kingdom in northwestern Anatolia.
Before Zipoetes I of Bithynia assumed the Greek title of Basileus ("king") in 297 BCE,[1] the positions of him and his predecessors are variously described as "prince",[2] "chieftain",[1] "ruler",[3] and "king".[4] One of the primary sources for the monarchs of Bithynia is About Hericlea (Ancient Greek: Περί Ηρακλείας, romanized: Peri Herakleias) of Memnon of Heraclea.[3]