登萨河 (保加利亚语：Тунджа；土耳其语：Tunca)是一条流经保加利亚和土耳其的河流，是马里查河最重要的一条支流。

扬博尔段登萨河

埃尔霍沃段登萨河

The Tùndzha (Bulgarian:Тунджа, Turkish:Tunca, Greek:Τόνζος) is a river in Bulgaria and Turkey and the most significant tributary of the Maritsa, emptying into it on Turkish territory near Edirne.

The river takes its source from the central parts of Stara Planina north of Kalofer, it then flows east and makes a sharp turn to the south before Yambol, in which direction it flows until it reaches the Maritsa. The Tundzha's length on Bulgarian territory is 350 km. It has about 50 tributaries, the more important of which Mochuritsa, Popovska and Sinapovska.