Lake Xynias or Xyniada (Greek: Λίμνη Ξυνιάς/Ξυνιάδα) was a lake in Central Greece.

The lake lay in a caldera of Mount Othrys, and measured approximately 5 km × 7 km, with a depth of 5 m.^[1] It was named after the nearby city of Xyniae.^[1] In the Middle Ages, it received the Slavic name Ezeros, after which the city was also renamed.^[2]

The lake was drained in 1936–42 to create arable farmland.