| Gusen | |
| Mouth Location: | Danube |
| Mouth Coordinates: | 48.2456°N 14.4989°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Austria |
| Subdivision Type2: | State |
| Subdivision Name2: | Upper Austria |
| Length Km: | 39.9 |
The Gusen is a small river in Upper Austria.
Including its source river German: Große Gusen, the Gusen is long. The German: Große Gusen flows through Reichenau im Mühlkreis and Gallneukirchen. It is joined by the German: Kleine Gusen at Breitenbruck, Katsdorf. The Gusen continues through Sankt Georgen an der Gusen. At Langenstein, near Mauthausen, the Gusen flows into the Danube.