| Welsh: Afon Lledr|italic=no | |
| Pushpin Map: | Wales |
| Pushpin Map Caption: | Location of mouth |
| Subdivision Type1: | Country |
| Subdivision Name1: | Wales |
| Length: | 16km (10miles) |
| Source1 Location: | the eastern slopes of Welsh: Ysgafell Wen|italic=no, which lies about 3 km NE of Welsh: [[Cnicht]]|italic=no |
| Mouth Location: | confluence with River Conwy |
The Welsh: Afon Lledr|italic=no (or the River Lledr) is a river in north-west Wales and the second major tributary of the River Conwy. It is about 10 miles or 16 km long, and flows in a generally easterly direction.
The Welsh: Lledr|italic=no has its source on the eastern slopes of Welsh: Ysgafell Wen|italic=no, which lies about 3 km NE of Welsh: [[Cnicht]]|italic=no. It initially flows in a north-easterly direction towards Welsh: Blaenau Dolwyddelan|italic=no, where Welsh: Ceunant Ty'n y Ddol|italic=no joins it, then flows under the Roman Bridge (Welsh: Pont-y-Sarn-Ddu) and past Welsh: [[Dolwyddelan]]|italic=no, where Welsh: Afon Penamnen|italic=no joins it. It continues to the north-east past Welsh: Pont-y-Pant|italic=no and then east along the Welsh: Lledr|italic=no|nocat=y Valley, running parallel to the A470 and the railway line from Welsh: [[Blaenau Ffestiniog]]|italic=no to Welsh: [[Llandudno]]|italic=no. This line has stations in the Welsh: Lledr|italic=no Valley at Roman Bridge, Welsh: [[Dolwyddelan railway station|Dolwyddelan]]|italic=no, and Welsh: [[Pont-y-Pant railway station|Pont-y-Pant]]|italic=no. The river joins the River Conwy to the south of Welsh: [[Betws-y-Coed]]|italic=no.