Experts digging in the lower Galilee region believe the ancient ruins show evidence of being used in the time of Jesus.
They say the synagogue dates to around 79AD when it was destroyed by the Romans who attacked Jerusalem.
It has been found at a site called Tel Rechesh, near to Mount Tabor (pictured) at the eastern end of the Jezreel Valley.
Dr. Motti Aviam of the Kineret Institute for Galilean Archaeology, said it's the "first synagogue discovered in the rural part of the Galilee and it confirms historical information we have about the New Testament, which says that Jesus preached at synagogues in Galilean villages."
He added: "The New Testament describes how Jesus delivered sermons in a synagogue in Capernaum and other synagogues in the Galilee... Christianity developed after he placed an emphasis on his sermons at synagogues in the Galilee.
"This makes the place very important for Christians."
The experts believe they have found evidence that many synagogues in the area Jesus lived were not used for worship and instead for meetings and study.
They believe this made them perfect places for Jesus to preach.