The city was founded around 688 BC, by colonists from Rhodos and Crete, 45 years after Syracuse and was named after the river Gela. The Greek playright Aischylos died here in 456 BC. From Gela, other parts of the island were also hellenized. In 405 BC, the city was sacked by Carthage. It was abandoned in 282 BC. The later city was founded in AD 1233 by Frederick II by the name Terranova di Sicilia until 1928, when it was changed back to Gela.

Much archeological research has taken place in and around the city and the archaeological museum exhibits many artefacts from the earlier periods of the city's history, among which a lot of vases. Both archaeology and writers from the classical period supply excellent sources for information on the earlier history of the city and surroundings.