The Rabnitz (Hungarian: Répce, Rábca) is a river in eastern Austria and northwestern Hungary. Its basin area is 4,506 km2.
The Rabnitz is formed at the confluence of its two headstreams Spratzbach and Thalbach near Hollenthon in Lower Austria. It flows towards the east through Burgenland, and enters Hungary near Répcevis. It receives the Hanság-főcsatorna, the canal that drains the Neusiedler See, from the left. It discharges into the Moson branch of the Danube near Győr.
