The Treklyanska reka (Bulgarian: Треклянска река) is a river in western Bulgaria, a right tributary of the Struma.

[1] The river takes its source under the name Melanshtitsa in Bohovska Planina at an altitude of 1,318 m, at 300 m southwest of the summit of Ogorelitsa (1,318 m) on the Bulgaria–Serbia border.

Except for two stretches near the villages of Treklyano and Peshtera, it flows in a deep narrow valley.

After receiving its largest tributary the Yavor, the river turns in direction south–southeast and after 6 km flows into the Struma at an altitude of 595 m in the northern areas of the town of Zemen.

In Pernik Province are situated the town of Zemen and the villages of Rayantsi, Kalotintsi, Vranya Stena and Peshtera in Zemen Municipality, as well as Gorna Melna, Dolna Melna and Dalga Luka in Tran Municipality.