| Große Aa | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Germany |
| Subdivision Type2: | State |
| Subdivision Name2: | Lower Saxony |
| Subdivision Type3: | Reference no. |
| Subdivision Name3: | DE: 34 |
| Length: | 35km (22miles) |
| Source1 Location: | Beginning: confluence of the Deeper Aa and Ahe east of Freren |
| Source1 Elevation: | (Deeper Aa, Ahe) |
| Mouth Location: | south of Lingen |
| Basin Landmarks: | Villages: Beesten, Lünne |
| Basin Size: | 922km2 |
| Tributaries Right: | Reitbach, Schinken Canal, Südbach |
| Tributaries Left: | Schaler Aa, Bardelgraben, Moosbeeke, Giegel Aa, Linner Graben, Speller Aa |
| Custom Label: | References |
The Große Aa is a 35adj=midNaNadj=mid, right, eastern tributary of the River Ems in western Lower Saxony (Germany).
It begins in the Samtgemeinde Freren, near the quarter of Overwater, at the confluence of the Deeper Aa and Ahe rivers. From there is flows through Lünne westwards to Hesselte, where it is joined by the Speller Aa. From there on it runs parallel to the Dortmund–Ems Canal and discharges into the Ems south of Lingen, a few metres north of the mouth of the canal after the Gleesen locks.