Aigialeia is a municipality and a former province in the eastern part of the Achaea regional unit, Greece. The seat of the municipality is the town Aigio. The main towns are Aigio, Akrata and Diakopto. The municipality Aigialeia stretches from the south coast of the Gulf of Corinth to the mountainous interior of the Peloponnese peninsula. The main rivers of the municipality are the Selinountas and the Vouraikos.
Present Aigialeia was the territory of the ancient Achaeans. Aigialeia was liberated in the first stage of the Greek War of Independence, in 1821. Aigio was struck by an earthquake in 1995, damaging several buildings. The 2007 Greek forest fires cause great damage in the mountains of Aigialeia.