Pastra (Greek: Πάστρα) is a village and a community in the southeastern part of the island of Kefalonia, Greece.

The community consists of the villages Pastra and Kremmydi.

According to 19th century Greek geographer and historian, Antonios Miliarakis, the village of Pastra and the area of the two villages (Kremmydi and Agios Giorgis) around it, used to be called Balta (later Valtes), and got its name from the many reeds and the streams it has.

The name Valtes is said to be of Albanian origin and means exactly that, "mud" or "swamp".

Albanian soldiers, from the Albanian colony of the Republic of Venice, inhabited the area during the 15th century when the Venetians gave them land in the "xomero" to settle with their families.