Syrmia (Serbian: Srem (Cyrillic: Срем), Croatian: Srijem) is a fertile region of the Pannonian plain in Europe, between the Danube and Sava rivers. It is divided between Serbia in the east and Croatia in the west.

Syrmia (Croatian: Srijem, Hungarian: Szerém, Serbian: Srem or Срем, Latin: Syrmia or Sirmium) is the name of administrative county (comitatus) of the autonomous region Croatia-Slavonia within the historic Kingdom of Hungary. Its territory is presently in eastern Croatia and north-western Serbia. The name Syrmia (Srem or Srijem) is still used for the corresponding regions in Serbia and Croatia.