Hippodamus of Miletus was a 5th-century BCE Greek architect, urban planner, and political theorist. He is best known for devising the orthogonal grid-based city layout known as the "Hippodamian plan," which he applied in designing the Athenian port of Piraeus, the city of Thurii, and Rhodes.

Aristotle identifies him as the first to theorize about an ideal political community without having practical political experience, describing him as an eccentric figure who also speculated on the natural universe. His systematic method divided city land into sacred, public, and private zones and categorized the population into three classes. His political treatise, On the Constitution, is lost and known only through Aristotle’s summary and critique in Politics. His theories on urban planning are likewise preserved through historical accounts rather than surviving independent works.

Hippodamus holds significance as the first recorded town planner in the Western tradition. His grid model became standard for Greek colonial cities and influenced Roman urban design. His rational, geometric approach to organizing both urban space and social structure marks an early important contribution to utopian political thought.