The Rezovo (also Rezovska, Rezvaya and Rezve; Bulgarian: Резовска река; Turkish: Mutludere) is a river in the extreme southeast of Bulgaria and northernmost part of European Turkey. The river is situated in Strandzha Nature Park.
The Rezovo is 112 km long and its source is in the Turkish part of the Strandzha mountains east of Kofçaz in Turkey under the Turkish name of Paspalderesi. It generally flows east from Turkey to Bulgaria, and after Paspala village of Kırklareli Province in Turkey becomes a border river between the Turkey and Bulgaria until its mouth in the Black Sea at Rezovo.
