Stomio (Greek: Στόμιο, before 1927: Τσάγεζι - Tsagezi) is a town in the Larissa regional unit, Thessaly, central Greece. It was the seat of the former municipality of Evrymenes. It is situated on the Aegean Sea coast, south of the mouth of the river Pineios, and at the foot of densely vegetated Mount Ossa. It is 13 km southeast of Pyrgetos, 17 km north of Agia and 37 km northeast of Larissa. Stomio is a popular beach resort. The landmark of Stomio is the lighthouse on the beach, near the port.
The ancient city Eurymenae (also Erymnae) was situated near present Stomio. The Greek Orthodox Monastery of Saint Demetrius, situated on the mountain slope above Stomio, was founded in the 6th century and rebuilt in its present form in the 12th century by Byzantine emperor Alexios I Komnenos.