Demenika 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 passes through the village, and the new Greek National Road 9 passes south of the village.