The Hadzhiyska reka (Bulgarian: Хаджийска река) is a 55 km long river in eastern Bulgaria that flows into the Black Sea.

[1] The river takes its source in the western part of the Eminska Planina division of the eastern Balkan Mountains at an altitude of 482 m, about two kilometers south of the village of Dobra Polyana.

In its first four kilometers the Hadzhiyska reka flows southwards and then turns east in a wide valley between the Eminska Planina to the north and the Aytoska Planina to the south.

Downstream of the village of Galabets its turns southeast, passes through the Poroy Reservoir and flows into the Nesabar Bay of the Black Sea in the southern part of Sunny Beach, the largest seaside resort in Bulgaria, and north of the town of Nesebar.

To the south the ridge of the Aytoska Planina forms the boundary with the drainage systems of the Aheloy.