Mesaio (Greek: Μεσαίο) is a village and a community of the Oraiokastro municipality.

[2] Before the 2011 local government reform it was part of the municipality of Kallithea, of which it was a municipal district.

[2] The 2021 census recorded 1,063 inhabitants in the community.

[1] The community of Mesaio covers an area of 27.896 km2.

[3] The community of Mesaio consists of three separate settlements:[1]