Casteltermini is a comune (municipality) in the Province of Agrigento in the Italian region Sicily, located about 70 kilometres (43 mi) southeast of Palermo and about 25 kilometres (16 mi) north of Agrigento.

Casteltermini borders the following municipalities: Acquaviva Platani, Aragona, Cammarata, Campofranco, San Biagio Platani, Sant'Angelo Muxaro, Santo Stefano Quisquina, Sutera.

Casteltermini was founded in 1629 by the local noble Gian Vincenzo Maria Termini e Ferreri, hence the name.

Casteltermini is noted for its extensive mines of rock salt and sulphur.

This Sicilian location article is a stub.