| Vadakste | |
| Pushpin Map: | Latvia |
| Subdivision Type1: | Country |
| Subdivision Name1: |  Latvia  Lithuania |
| Length: | 82.2km (51.1miles) |
| Discharge1 Avg: | 95m3/s |
| Source1 Elevation: | 43m (141feet) |
| Mouth Location: | Venta River |
| Basin Size: | 1230km2 |
| Tributaries Left: | , Agluona, |
| Tributaries Right: | Līgotne, Avīkne, Benaišu strauts, Burbuļ strauts, Alkšņupe,, Suste, Rīku strauts, Pestīle |
The Vadakste (Lithuanian: Vadakstis) is a river in southern Latvia and northern Lithuania. It is a right tributary of the Venta River. The length is 82.2km (51.1miles), of which over 55km (34miles) follow the Latvia–Lithuania border. The catchment area is 1230km2.[1] It originates near the city Auce, Latvia. It flows first in a southwest, and then in a westerly direction. It begins to flow along the border between Latvia and Lithuania from the village of Vegeriai. It flows into Venta at 184.2km (114.5miles) from its mouth, in the village of Griežė, 2km (01miles) northwest of Leckava.
The main tributaries:,, Agluona and Avīkne. The average river slope is 73 cm/km.[2]