Demenika (Greek: Δεμένικα) is a village/suburb in the municipality of Patras, Achaea, Greece.

It lies 5 kilometres (3.1 mi) south of the city centre, south of the river Glafkos.

It is part of the community of Saravali within the municipal unit of Messatida.

It is 2 km northeast of Ovrya and 4 km east of Paralia.

The Greek National Road 33 (Patras - Tripoli) passes through the village, and the new Greek National Road 9 (Patras - Pyrgos) passes south of the village.