Aristonicus of Tarentum (Ἀριστόνικος ὁ Ταραντῖνος) was a Greek author from Tarentum in southern Italy, active in the 4th or 3rd century BCE. A shadowy figure, no details of his personal life survive beyond his origin in that major Doric colony.

His sole known work is the lost treatise On the Wanderings of Io (Περὶ τῆς Ἰοῦς πλάνης). Surviving fragments indicate it was a mythological-geographical text tracing the route of the mythical Io to explain place names like the Ionian Sea. The geographer Strabo quotes from it [1].

Aristonicus is significant as a source for later scholars. His work was consulted by the Homeric commentator Aristarchus of Samothrace, as noted in the scholia to the Iliad [2]. His fragments represent the Hellenistic periegetic tradition, using myth to explicate geography and contributing to the scholarly study of Homeric references.

Sources 1. Strabo, Geography: https://www.perseus.tufts.edu/hopper/text?doc=Strab.+1.2.35&fromdoc=Perseus%3Atext%3A1999.01.0239 2. Scholia to Homer's Iliad: https://topostext.org/work/741#2.494 3. Smith's Dictionary of Greek and Roman Biography and Mythology: https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0104%3Aentry%3Daristonicus-bio-2